Earnings per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income attributable to common shareholders - basic	$ 145	$ 201	$ 395	$ 478
Add: Net income attributable to noncontrolling interests	78	150	215	376
Net income available to common shareholders and noncontrolling interests - diluted	$ 223	$ 351	$ 610	$ 854
Denominator:
Weighted average common shares - basic (shares)	303	267	301	258
Exchange of noncontrolling interests for common shares (in shares)	162	197	164	204
Effect of other dilutive securities (in shares)	5	6	4	7
Weighted average common shares - diluted (in shares)	470	470	469	469
Basic earnings per share (in usd per share)	$ 0.48	$ 0.76	$ 1.31	$ 1.85
Diluted earnings per share (in usd per share)	$ 0.47	$ 0.75	$ 1.30	$ 1.82
Anti-dilutive securities outstanding (in shares)	8	3	8	3