Derivatives - Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2016
After-tax Derivative Activity recorded in AOCI
Unrealized losses on derivatives	$ (2)	$ (14)
Reclassification to income of realized losses (gains) on derivatives		$ 7

Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax 1

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration