Derivative Instruments - Impact on Statements of Income, Fair Value Hedges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Gains/(losses) recorded in income
Derivatives	$ (1,907)	$ (726)	$ (9,730)	$ 3,895
Hedged items	2,522	1,056	11,307	(2,881)
Income statement impact	615	330	1,577	1,014
Income statement impact of excluded components:
Amortization approach	(71)	(79)	(221)	(379)
Changes in fair value	609	350	1,648	984
OCI impact
Derivatives - Gains/(losses) recorded in OCI	12	(91)	(56)	45
Interest rate
Gains/(losses) recorded in income
Derivatives	(812)	(464)	(3,749)	4,087
Hedged items	1,401	743	5,217	(3,333)
Income statement impact	589	279	1,468	754
Income statement impact of excluded components:
Amortization approach	0	0	0	0
Changes in fair value	592	309	1,572	728
OCI impact
Derivatives - Gains/(losses) recorded in OCI	0	0	0	0
Foreign exchange
Gains/(losses) recorded in income
Derivatives	(363)	307	(862)	579
Hedged items	367	(280)	893	(430)
Income statement impact	4	27	31	149
Income statement impact of excluded components:
Amortization approach	(71)	(79)	(221)	(379)
Changes in fair value	3	27	30	149
OCI impact
Derivatives - Gains/(losses) recorded in OCI	12	(91)	(56)	45
Commodity
Gains/(losses) recorded in income
Derivatives	(732)	(569)	(5,119)	(771)
Hedged items	754	593	5,197	882
Income statement impact	22	24	78	111
Income statement impact of excluded components:
Amortization approach	0	0	0	0
Changes in fair value	14	14	46	107
OCI impact
Derivatives - Gains/(losses) recorded in OCI	$ 0	$ 0	$ 0	$ 0