Net Income 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:
Income from continuing operations	$ 740	$ 400	$ 1,225	$ 916
Income from discontinued operations, net of income taxes	6	2	2,933	4
Net income	$ 746	$ 402	$ 4,158	$ 920
Denominator:
Weighted average shares of common stock - basic (in shares)	703	860	728	880
Dilutive effect of equity incentive awards (in shares)	8	7	6	7
Weighted average shares of common stock - diluted (in shares)	711	867	734	887
Income per share - basic:
Continuing operations (in usd per share)	$ 1.05	$ 0.47	$ 1.68	$ 1.04
Discontinued operations (in usd per share)	0.01	0	4.03	0.01
Net income per share - basic (in usd per share)	1.06	0.47	5.71	1.05
Income per share - diluted:
Continuing operations (in usd per share)	1.04	0.46	1.67	1.03
Discontinued operations (in usd per share)	0.01	0	4.00	0.01
Net income per share - diluted (in usd per share)	$ 1.05	$ 0.46	$ 5.67	$ 1.04
Common stock equivalents excluded from income per diluted share because their effect would have been anti-dilutive (in shares)	1	20	6	23