Supplemental Financial Statement Information (Reclassifications Out of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues	$ 182,527	$ 161,857	$ 136,819
Other income (expense), net	6,858	5,394	7,389
Benefit (provision) for income taxes	(7,813)	(5,282)	(4,177)
Net of tax	40,269	34,343	30,736
Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	629	410	813
Reclassification out of AOCI | Unrealized gains (losses) on available-for-sale investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net	650	149	1,190
Benefit (provision) for income taxes	(137)	(38)	(279)
Net of tax	513	111	911
Reclassification out of AOCI | Unrealized Gains (Losses) on Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Benefit (provision) for income taxes	(34)	(74)	35
Net of tax	116	299	(98)
Reclassification out of AOCI | Unrealized Gains (Losses) on Cash Flow Hedges | Foreign exchange contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues	144	367	(139)
Reclassification out of AOCI | Unrealized Gains (Losses) on Cash Flow Hedges | Interest rate contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net	$ 6	$ 6	$ 6