Non-Wholly Owned Entities and Contingently Redeemable Noncontrolling Interest - Redeemable Noncontrolling Interest (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Increase (Decrease) in Redeemable Noncontrolling Interest [Roll Forward]
Balance as of December 31, 2015			$ 0
Reclassification of noncontrolling interest			46
Net income attributable to noncontrolling interest	$ 3	$ 2	14	$ 14
Distribution to noncontrolling interest			(19)	(18)
Balance as of June 30, 2016	$ 41	$ 0	$ 41	$ 0