Earnings per Share (Unaudited) 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
Earnings Per Share [Abstract]
Net income (loss) from continuing operations	$ 432	$ (235)	$ 7	$ (234)
Net (income) loss from continuing operations attributable to noncontrolling interests	(103)	27	(116)	(16)
Undistributed earnings allocated to participating securities	(3)	(3)	(3)	(3)
Net income (loss) from continuing operations attributable to common stockholders	326	(211)	(112)	(253)
Net income from discontinued operations attributable to common stockholders	0	1	0	2
Net income (loss) attributable to common stockholders	$ 326	$ (210)	$ (112)	$ (251)
Basic weighted-average shares of common stock outstanding	1,453	1,452	1,453	1,451
Add shares issuable upon exercise or vesting of dilutive stock options and restricted stock units (RSUs)a	8	0	0	0
Diluted weighted-average shares of common stock outstanding	1,461	1,452	1,453	1,451
Basic and diluted net income (loss) per share attributable to common stockholders:
Continuing operations (in dollars per share)	$ 0.22	$ (0.15)	$ (0.08)	$ (0.17)
Discontinued operations (in dollars per share)	0	0	0	0
Earnings per share, basic (in dollars per share)	$ 0.22	$ (0.15)	$ (0.08)	$ (0.17)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2	10	13	11
Dilutive Securities Excluded from Computation of EPS Amount	28	43	35	42