Income Taxes - Items Accounting for Differences Between Income Taxes Computed at Federal Statutory Rate and Provision Recorded for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income taxes computed at the federal statutory rate									$ 2,935	$ 2,365	$ 1,332
Effect of:
Tax impact of foreign earnings									381	119	1,178
State taxes, net of federal benefits									221	263	114
Tax credits									(466)	(419)	(220)
Stock-based compensation									(850)	(1,086)	(917)
2017 Impact of U.S. Tax Act									0	(157)	(789)
Other, net									153	112	71
Provision for income taxes, net	$ 786	$ 494	$ 257	$ 836	$ 327	$ 508	$ 74	$ 287	2,374	1,197	769
Excess tax benefits from stock-based compensation									$ 1,400	$ 1,600	$ 1,300