Total Equity and Other Comprehensive Income (Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax [Abstract]
Net unrealized gains (losses) on securities, pre-tax	$ (1,998)	$ (320)	$ (11,245)	$ (1,446)
Less: Net realized gains (losses) reclassified to earnings	(260)	3	(477)	25
Net increase (decrease), pre-tax	(1,738)	(323)	(10,768)	(1,471)
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax [Abstract]
Net unrealized gains (losses) on securities, tax effect	471	76	2,650	341
Less: Net realized gains (losses) reclassified to earnings, tax effect	61	(1)	112	(6)
Effect of income taxes	410	77	2,538	347
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, After Reclassification Adjustments, after Tax [Abstract]
Net unrealized gains (losses) on securities, after tax	(1,527)	(244)	(8,595)	(1,105)
Less: Net realized gains (losses) reclassified to earnings, after tax	(199)	2	(365)	19
Net increase (decrease), after-tax	(1,328)	(246)	(8,230)	(1,124)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax [Abstract]
Net unrealized gains (losses) on cash flow hedges, pre-tax	(1,154)	(59)	(3,486)	(369)
Less: Net realized gains (losses) reclassified to earnings, pre-tax	(129)	115	(2)	358
Net increase (decrease), pre-tax	(1,025)	(174)	(3,484)	(727)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax [Abstract]
Net unrealized gains (losses) on cash flow hedges, tax effect	272	14	821	87
Less: Net realized gains (losses) reclassified to earnings, tax effect	30	(27)		(84)
Effect of income taxes	242	41	821	171
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Net unrealized gains (losses) on cash flow hedges, after tax	(882)	(45)	(2,665)	(282)
Less: Net realized gains (losses) reclassified to earnings, after tax	(99)	88	(2)	274
Net increase (decrease), after-tax	(783)	(133)	(2,663)	(556)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, before Tax [Abstract]
Net pension and other postretirement benefit plan activity and other reclassified to earnings, pre-tax	2	2	64	(11)
Net increase (decrease), pre-tax	2	2	64	(11)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax [Abstract]
Net pension and other postretirement benefit plan activity and other reclassified to earnings, tax effect	(1)		(16)	3
Effect of income taxes	(1)		(16)	3
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract]
Net pension and other postretirement benefit plan activity and other reclassified to earnings, after-tax	1	2	48	(8)
Net increase (decrease), after-tax	1	2	48	(8)
Other Comprehensive Income Other Adjustments [Abstract]
Net unrealized gains (losses) on other transactions, pre-tax	4	1	(3)	2
Net increase (decrease), pre-tax	4	1	(3)	2
Net unrealized gains (losses) on other transactions, tax effect	(22)	(8)	(47)	(5)
Effect of income taxes	(22)	(8)	(47)	(5)
Net unrealized gains (losses) on other transactions, after tax	(18)	(7)	(50)	(3)
Net increase (decrease), after-tax	(18)	(7)	(50)	(3)
Other comprehensive income (loss), before tax and net of reclassifications into Net income	(2,757)	(494)	(14,191)	(2,207)
Total other comprehensive income (loss), tax effect	629	110	3,296	516
Other comprehensive income (loss), after tax and net of reclassifications into Net income	$ (2,128)	$ (384)	$ (10,895)	$ (1,691)