Other Comprehensive Income (Accumulated Other Comprehensive Income (Loss) Components) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023		Dec. 31, 2022		Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, Beginning Balance	[1]	$ 45,812.0		$ 55,726.0		$ 54,041.0
Other comprehensive income (loss), net of tax		2,460.0		(10,581.0)		(2,361.0)
Equity, Ending Balance	[1]	51,141.0		45,812.0		55,726.0
Pretax loss from derivatives		293.0		314.0
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, Beginning Balance	[1]	(10,172.0)	[2]	409.0		2,770.0
Other comprehensive income (loss), net of tax		2,460.0		(10,581.0)		(2,361.0)
Equity, Ending Balance	[1]	(7,712.0)	[2]	(10,172.0)	[2]	409.0
Debt securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, Beginning Balance		(7,164.0)	[2]	589.0		2,462.0
Other comprehensive income (loss), net of tax		1,334.0		(7,753.0)		(1,873.0)
Equity, Ending Balance		(5,830.0)	[2]	(7,164.0)	[2]	589.0
Cash flow hedge derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, Beginning Balance		(2,705.0)	[2]	(201.0)		659.0
Other comprehensive income (loss), net of tax		992.0		(2,504.0)		(860.0)
Equity, Ending Balance		(1,713.0)	[2]	(2,705.0)	[2]	(201.0)
Pension and other postretirement benefit plan adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, Beginning Balance		(251.0)	[2]	27.0		(345.0)
Other comprehensive income (loss), net of tax		126.0		(278.0)		372.0
Equity, Ending Balance		(125.0)	[2]	(251.0)	[2]	27.0
Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity, Beginning Balance		(52.0)	[2]	(6.0)		(6.0)
Other comprehensive income (loss), net of tax		8.0		(46.0)
Equity, Ending Balance		$ (44.0)	[2]	$ (52.0)	[2]	$ (6.0)

[1] The par value of our preferred stock outstanding was less than $0.5 million at each date and, therefore, is excluded from this presentation.

[2] AOCI included pretax losses of $293 million and $314 million from derivatives that hedged the purchase of investment securities classified as held to maturity at December 31, 2023 and December 31, 2022, respectively.