| **Condensed Consolidating Guarantor and Non-Guarantor Financial Information - Guarantor and Non-Guarantor Parenthetical (Details) (USD $)In Millions, unless otherwise specified** | 3 Months Ended | 9 Months Ended |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| Defined benefit plan, tax                                                                                                                                                          | $ (3)          | $ 1            | $ (4) | $ 2 |
| Parent Company [Member]                                                                                                                                                            |           |           |   |   |
| Defined benefit plan, tax                                                                                                                                                          | (3)            | 1              | (4) | 2 |
| Guarantor Subsidiaries [Member]                                                                                                                                                    |           |           |   |   |
| Defined benefit plan, tax                                                                                                                                                          | 0              | 0              | 0 | 0 |
| Non-Guarantor Subsidiaries [Member]                                                                                                                                                |           |           |   |   |
| Defined benefit plan, tax                                                                                                                                                          | (3)            | 1              | (4) | 2 |
| Consolidation, Eliminations [Member]                                                                                                                                               |           |           |   |   |
| Defined benefit plan, tax                                                                                                                                                          | $ 3            | $ (1)          | $ 4 | $ (2) |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of tax (expense) benefit, after reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans, attributable to parent entity.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569643-111683Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569616-111683Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684
+ Details**Name:**us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |