Basis of Presentation - Redeemable Non Controlling Interest (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Redeemable Noncontrolling Interest [Roll Forward]
Balance at beginning of period	$ 78	$ 196
Net income (loss) attributable to redeemable noncontrolling interests	13	5
Other comprehensive income (loss)	(1)	(4)
Noncontrolling interest tender offer redemption	0	(46)
Redemption value measurement adjustment	18	10
Reclassification of noncontrolling interest to permanent equity	0	(82)
Balance at end of period	$ 108	$ 79