Derivative Instruments - Schedule of Recognized Gains or Losses Related to Derivative Instruments Designated as Hedging Instruments and not Designated as Hedging Instruments (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
Derivative Instruments, Gain (Loss) [Line Items]
Total amounts presented in the consolidated statements of income in which the effects of cash flow hedges are recorded	$ 4,961	$ 4,378	$ 4,305	$ 4,128	$ 4,226	$ 3,683	$ 3,857	$ 3,685	$ 17,772	$ 15,451	$ 13,094
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized from foreign exchange contracts									24	45	(54)
Foreign Exchange Contract | Net Revenues | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized from foreign exchange contracts									238	(30)	17
Foreign Exchange Contract | Net Revenues | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized from foreign exchange contracts									0	7	0
Foreign Exchange Contract | Other Income (Expense) | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized from foreign exchange contracts									$ 24	$ 38	$ (54)