| **Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (USD $)In Millions, unless otherwise specified** | Total    | Common stock [Member] | Additional paid-in capital [Member] | Retained earnings [Member] | Accumulated other comprehensive income (loss) [Member] | Treasury stock [Member] | Notes receivable for the issuance of common stock [Member] |
|--------------------------------------------------------------------------------------------------------------------------|----------|-----------------------|-------------------------------------|----------------------------|--------------------------------------------------------|-------------------------|------------------------------------------------------------|
| Balance at Dec. 31, 2012                                                                                                 |     | $ 683                 | $ 2,146                             | $ 8,774                    | $ 831                                                  | $ (99)                  | $ (21)                                                     |
| **Increase (Decrease) in Stockholders' Equity [Roll Forward]**                                                           |     |                  |                                |                       |                                                   |                    |                                                       |
| Net income (loss)                                                                                                        | 444      |                  |                                | 444                        |                                                   |                    |                                                       |
| Other comprehensive income (loss), net of tax                                                                            | (705)    |                  |                                |                       | (705)                                                  |                    |                                                       |
| Dividends paid to common stockholders                                                                                    |     |                  |                                | (108)                      |                                                   |                    |                                                       |
| Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures                                          |     |                  | (6)                                 |                       |                                                   | 8                       |                                                       |
| (Increase) Decrease in notes receivable from the issuance of common stock                                                |     |                  |                                |                       |                                                   |                    | (3)                                                        |
| Balance at Jun. 30, 2013                                                                                                 | 11,944   | 683                   | 2,140                               | 9,110                      | 126                                                    | (91)                    | (24)                                                       |
| Balance at Dec. 31, 2013                                                                                                 | 12,651   | 683                   | 2,145                               | 9,495                      | 442                                                    | (91)                    | (23)                                                       |
| Decrease (increase) in notes receivable for common stock                                                                 |     |                  |                                |                       |                                                   |                    | 22                                                         |
| **Increase (Decrease) in Stockholders' Equity [Roll Forward]**                                                           |     |                  |                                |                       |                                                   |                    |                                                       |
| Net income (loss)                                                                                                        | 280      |                  |                                | 280                        |                                                   |                    |                                                       |
| Other comprehensive income (loss), net of tax                                                                            | 520      |                  |                                |                       | 520                                                    |                    |                                                       |
| Dividends paid to common stockholders                                                                                    |     |                  |                                | (406)                      |                                                   |                    |                                                       |
| Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures                                          |     |                  | 1                                   |                       |                                                   | 6                       |                                                       |
| Balance at Jun. 30, 2014                                                                                                 | $ 13,074 | $ 683                 | $ 2,146                             | $ 9,369                    | $ 962                                                  | $ (85)                  | $ (1)                                                      |

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Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.
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Amount after tax and reclassification adjustments of other comprehensive income (loss).
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Value of stock (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP), net of stock value of such awards forfeited. Stock issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.
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