Earnings per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net income attributable to common shareholders - basic	$ 106	$ 142	$ 250	$ 277
Add: Net income attributable to noncontrolling interests	57	115	137	226
Net income available to common shareholders and noncontrolling interests - diluted	$ 163	$ 257	$ 387	$ 503
Denominator:
Weighted average common shares - basic (shares)	301	255	300	254
Exchange of noncontrolling interests for common shares (in shares)	164	207	165	207
Effect of other dilutive securities (in shares)	4	7	4	7
Weighted average common shares - diluted (in shares)	469	469	469	468
Basic earnings per share (in usd per share)	$ 0.35	$ 0.56	$ 0.83	$ 1.09
Diluted earnings per share (in usd per share)	$ 0.35	$ 0.55	$ 0.83	$ 1.07
Anti-dilutive securities outstanding (in shares)	8	3	8	3