Financial Instruments - Cash Flow Hedges After-tax Gains/(Losses) (Details) - Cash Flow Hedges - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
After-tax gains (losses) reclassified from accumulated other comprehensive income/(loss)	$ 168	$ (109)	$ (199)
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
After-tax gains (losses) reclassified from accumulated other comprehensive income into earnings/(losses)	155	(161)	(154)
After-tax gains (losses) reclassified from accumulated other comprehensive income/(loss)	168	(107)	(202)
Currency exchange contracts \| Forecasted transactions
Derivative Instruments, Gain (Loss) [Line Items]
After-tax gains (losses) reclassified from accumulated other comprehensive income/(loss)	$ 0	$ (2)	$ 3

Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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