| **Rosetta Merger - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Millions** | 3 Months Ended | 9 Months Ended |
|---------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Business Combinations [Abstract]**                                                              |           |           |   |   |
| Revenues                                                                                          | $ 828          | $ 1,557        | $ 2,582 | $ 4,828 |
| Net income                                                                                        | $ (202)        | $ 542          | $ (338) | $ 1,039 |
| **Earnings per share:**                                                                           |           |           |   |   |
| Basic (in dollars per share)                                                                      | $ (0.44)       | $ 1.37         | $ (0.79) | $ 2.63 |
| Diluted (in dollars per share)                                                                    | $ (0.44)       | $ 1.35         | $ (0.79) | $ 2.59 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(2)-(3) -URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.
+ References
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| - References
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