Redeemable Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning			$ 12
Share of profit or loss attributable to redeemable noncontrolling interests	$ 3	$ 1	7	$ 5
Dividends paid	2	1	2	2
Balance at end	47		47		$ 12
Payments to Acquire Additional Interest in Subsidiaries					14
Redeemable Noncontrolling Interest
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning			98	99	99
Impact of foreign exchange translation			2	17
Share of profit or loss attributable to redeemable noncontrolling interests			4	3
Redemption value adjustment for the current period			1	(5)
Dividends paid				(2)
Measurement period adjustments				(1)
Exercises of redeemable noncontrolling interests				11
Balance at end	$ 105	$ 100	$ 105	$ 100	$ 98