Total Equity and Other Comprehensive Income (Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pre-tax
Other comprehensive loss, before tax and net of reclassifications into Net income	$ (965)	$ (2,757)	$ (123)	$ (14,191)
Tax effect
Total other comprehensive income (loss)	229	629	34	3,296
After-tax
Other comprehensive income loss, after tax and net of reclassifications into Net income	(736)	(2,128)	(89)	(10,895)
Debt securities
Pre-tax
Net unrealized gains (losses)	(1,171)	(1,998)	(993)	(11,245)
Less: Net realized gains (losses) reclassified to earnings	(239)	(260)	(689)	(477)
Other comprehensive loss, before tax and net of reclassifications into Net income	(932)	(1,738)	(304)	(10,768)
Tax effect
Net unrealized gains (losses)	280	471	238	2,650
Less: Net realized gains (losses) reclassified to earnings	57	61	163	112
Total other comprehensive income (loss)	223	410	75	2,538
After-tax
Net unrealized gains (losses)	(891)	(1,527)	(755)	(8,595)
Less: Net realized gains (losses) reclassified to earnings	(182)	(199)	(526)	(365)
Other comprehensive income loss, after tax and net of reclassifications into Net income	(709)	(1,328)	(229)	(8,230)
Cash flow hedge derivatives
Pre-tax
Net unrealized gains (losses)	(461)	(1,154)	(953)	(3,486)
Less: Net realized gains (losses) reclassified to earnings	(426)	(129)	(1,129)	(2)
Other comprehensive loss, before tax and net of reclassifications into Net income	(35)	(1,025)	176	(3,484)
Tax effect
Net unrealized gains (losses)	122	272	238	821
Less: Net realized gains (losses) reclassified to earnings	112	30	278
Total other comprehensive income (loss)	10	242	(40)	821
After-tax
Net unrealized gains (losses)	(339)	(882)	(715)	(2,665)
Less: Net realized gains (losses) reclassified to earnings	(314)	(99)	(851)	(2)
Other comprehensive income loss, after tax and net of reclassifications into Net income	(25)	(783)	136	(2,663)
Pension and  other postretirement benefit plan adjustments
Pre-tax
Less: Net realized gains (losses) reclassified to earnings	1	2	(3)	64
Other comprehensive loss, before tax and net of reclassifications into Net income	1	2	(3)	64
Tax effect
Less: Net realized gains (losses) reclassified to earnings	(1)	(1)		(16)
Total other comprehensive income (loss)	(1)	(1)		(16)
After-tax
Less: Net realized gains (losses) reclassified to earnings		1	(3)	48
Other comprehensive income loss, after tax and net of reclassifications into Net income		1	(3)	48
Other
Pre-tax
Less: Net realized gains (losses) reclassified to earnings	1	4	8	(3)
Other comprehensive loss, before tax and net of reclassifications into Net income	1	4	8	(3)
Tax effect
Less: Net realized gains (losses) reclassified to earnings	(3)	(22)	(1)	(47)
Total other comprehensive income (loss)	(3)	(22)	(1)	(47)
After-tax
Less: Net realized gains (losses) reclassified to earnings	(2)	(18)	7	(50)
Other comprehensive income loss, after tax and net of reclassifications into Net income	$ (2)	$ (18)	$ 7	$ (50)