Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Income from continuing operations	$ 283	$ 605	$ 1,145	$ 1,715
Income (loss) from discontinued operations, net of income taxes	(19)	59	10,494	3,107
Net income	$ 264	$ 664	$ 11,639	$ 4,822
Denominator:
Weighted average shares of common stock - basic (in shares)	647	696	667	717
Dilutive effect of equity incentive awards (in shares)	11	12	11	8
Weighted average shares of common stock - diluted (in shares)	658	708	678	725
Income (loss) per share - basic:
Continuing operations (in usd per share)	$ 0.44	$ 0.87	$ 1.72	$ 2.39
Discontinued operations (in usd per share)	(0.03)	0.08	15.72	4.33
Net income per share - basic (in usd per share)	0.41	0.95	17.44	6.72
Income (loss) per share - diluted:
Continuing operations (in usd per share)	0.43	0.86	1.69	2.37
Discontinued operations (in usd per share)	(0.03)	0.08	15.47	4.28
Net income per share - diluted (in usd per share)	$ 0.40	$ 0.94	$ 17.16	$ 6.65
Common stock equivalents excluded from income per diluted share because their effect would have been anti-dilutive (in shares)	0	0	9	1