Derivative Instruments - Change in Unrealized Gains (Losses) in AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	$ 243	$ 539	$ 1,344
Ending Balance	701	243	539
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(1)	(1)	(3)
Other comprehensive income before reclassifications	7	0	2
Reclassifications from accumulated other comprehensive loss to net earnings	(4)	0	0
Ending Balance	$ 2	$ (1)	$ (1)