Derivative instruments (Summary of Income and Expense Line Items) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Total revenues	$ 6,238	$ 5,901
Other (expense) income, net	(530)	13
Interest expense, net	(295)	(285)
Interest rate swap agreements [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on fair value hedging relationships, Hedged items	337	175
Gains (losses) on fair value hedging relationships, Derivatives designated as hedging instruments	(315)	(152)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Cash flow hedges [Member] | Cross-currency swap contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other (expense) income, net	(78)	(132)
Product sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total revenues	5,731	5,592
Product sales [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Cash flow hedges [Member] | Foreign currency contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total revenues	$ 27	$ (1)