Total Equity and Other Comprehensive Income (Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pre-tax
Other comprehensive income (loss), before tax and net of reclassifications into Net income	$ (433)	$ 1,390
Tax effect
Total other comprehensive income (loss)	103	(326)
After-tax
Other comprehensive income (loss), after tax and net of reclassifications into Net income	(330)	1,064
Debt securities
Pre-tax
Net unrealized gains (losses)	(395)	654
Less: Net realized gains (losses) reclassified to earnings	(216)	(215)
Other comprehensive income (loss), before tax and net of reclassifications into Net income	(179)	869
Tax effect
Net unrealized gains (losses)	95	(154)
Less: Net realized gains (losses) reclassified to earnings	52	51
Total other comprehensive income (loss)	43	(205)
After-tax
Net unrealized gains (losses)	(300)	500
Less: Net realized gains (losses) reclassified to earnings	(164)	(164)
Other comprehensive income (loss), after tax and net of reclassifications into Net income	(136)	664
Cash flow hedge derivatives
Pre-tax
Net unrealized gains (losses)	(626)	197
Less: Net realized gains (losses) reclassified to earnings	(376)	(330)
Other comprehensive income (loss), before tax and net of reclassifications into Net income	(250)	527
Tax effect
Net unrealized gains (losses)	150	(46)
Less: Net realized gains (losses) reclassified to earnings	90	78
Total other comprehensive income (loss)	60	(124)
After-tax
Net unrealized gains (losses)	(476)	151
Less: Net realized gains (losses) reclassified to earnings	(286)	(252)
Other comprehensive income (loss), after tax and net of reclassifications into Net income	(190)	403
Pension and  other postretirement benefit plan adjustments
Pre-tax
Less: Net realized gains (losses) reclassified to earnings	(2)	(10)
Other comprehensive income (loss), before tax and net of reclassifications into Net income	(2)	(10)
Tax effect
Less: Net realized gains (losses) reclassified to earnings		2
Total other comprehensive income (loss)		2
After-tax
Less: Net realized gains (losses) reclassified to earnings	(2)	(8)
Other comprehensive income (loss), after tax and net of reclassifications into Net income	(2)	(8)
Other
Pre-tax
Less: Net realized gains (losses) reclassified to earnings	(2)	4
Other comprehensive income (loss), before tax and net of reclassifications into Net income	(2)	4
Tax effect
Less: Net realized gains (losses) reclassified to earnings		1
Total other comprehensive income (loss)		1
After-tax
Less: Net realized gains (losses) reclassified to earnings	(2)	5
Other comprehensive income (loss), after tax and net of reclassifications into Net income	$ (2)	$ 5