Total Equity and Other Comprehensive Income (Accumulated Other Comprehensive Income (Loss) Components) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Equity, Beginning Balance	$ 51,141	$ 45,812
Other comprehensive income (loss), net of tax	(330)	1,064
Equity, Ending Balance	51,374	49,074
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Equity, Beginning Balance	(7,712)	(10,172)
Other comprehensive income (loss), net of tax	(330)	1,064
Equity, Ending Balance	(8,042)	(9,108)
Debt securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Equity, Beginning Balance	(5,830)	(7,164)
Other comprehensive income (loss), net of tax	(136)	664
Equity, Ending Balance	(5,966)	(6,500)
Cash flow hedge derivatives
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Equity, Beginning Balance	(1,713)	(2,705)
Other comprehensive income (loss), net of tax	(190)	403
Equity, Ending Balance	(1,903)	(2,302)
Pension and  other postretirement benefit plan adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Equity, Beginning Balance	(125)	(251)
Other comprehensive income (loss), net of tax	(2)	(8)
Equity, Ending Balance	(127)	(259)
Other
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Equity, Beginning Balance	(44)	(52)
Other comprehensive income (loss), net of tax	(2)	5
Equity, Ending Balance	$ (46)	$ (47)