Income Taxes - Reconciliation of Income Tax Expense Computed Using U.S. Statutory Federal Tax Rate to Actual Income Tax Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amount
Income tax expense at the U.S. federal statutory tax rate	$ 1,521	$ 1,226	$ 1,836
Research and development tax credit	(148)	(138)	(115)
Foreign derived intangible income deduction	(122)	(61)	0
Excess tax benefits for share-based payment awards	(63)	(55)	(106)
Tax deductible dividends	(62)	(59)	(94)
Tax accounting method change	(15)	(61)	0
Deferred tax write-down and transition tax	0	(43)	1,886
U.S. manufacturing deduction benefit	0	0	(7)
Other, net	(100)	(17)	(44)
Total income tax expense	$ 1,011	$ 792	$ 3,356
Rate
Income tax expense at the U.S. federal statutory tax rate	21.00%	21.00%	35.00%
Research and development tax credit	(2.00%)	(2.40%)	(2.20%)
Foreign derived intangible income deduction	(1.70%)	(1.00%)	0.00%
Excess tax benefits for share-based payment awards	(0.90%)	(0.90%)	(2.00%)
Tax deductible dividends	(0.90%)	(1.00%)	(1.80%)
Tax accounting method change, percent	(0.20%)	(1.00%)	0.00%
Deferred tax write-down and transition tax	0	(0.007)	0.359
U.S. manufacturing deduction benefit	0.00%	0.00%	(0.10%)
Other, net (d)	(1.30%)	(0.40%)	(0.80%)
Income tax expense	14.00%	13.60%	64.00%
Tax accounting method change	$ (15)	$ (61)	$ 0