Total Equity and Other Comprehensive Income (Rollforward of Total Equity) (Details) $ / shares in Units, $ in Millions		3 Months Ended
	Feb. 07, 2023 $ / shares shares	Mar. 31, 2023 USD ($) shares	Mar. 31, 2022 USD ($) shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Common Stock [Abstract]
Equity, Beginning Balance		$ 45,812.0	$ 55,726.0
Net income		1,694.0	1,429.0
Other comprehensive income (loss), net of tax		1,064.0	(6,140.0)
Dividends, Cash [Abstract]
Common		(607.0)	(531.0)
Preferred		(68.0)	(45.0)
Preferred stock discount accretion
Preferred stock issuance		1,487.0
Treasury stock activity		(238.0)	(1,189.0)
Other		(96.0)	(34.0)
Equity, Ending Balance		49,074.0	49,216.0
Preferred stock, par value		0.5	$ 0.5	$ 0.5	$ 0.5
Cumulative Effect, Period of Adoption, Adjustment
Common Stock [Abstract]
Equity, Beginning Balance		26.0
Cumulative Effect, Period of Adoption, Adjusted Balance
Common Stock [Abstract]
Equity, Beginning Balance		$ 45,838.0
Series W
Dividends, Cash [Abstract]
Depositary shares conversion ratio	0.01
Common stock activity (shares) | shares	1,500,000
Fixed interest rate	6.25%
Preferred stock, par or stated value per share (in dollars per share) | $ / shares	$ 1
Common Stock
Common Stock [Abstract]
Beginning Balance (in shares) | shares		401,000,000	420,000,000
Treasury stock activity, shares | shares		(2,000,000)	(5,000,000)
Ending Balance, (in shares) | shares		399,000,000	415,000,000
Equity, Beginning Balance		$ 2,714.0	$ 2,713.0
Dividends, Cash [Abstract]
Equity, Ending Balance		$ 2,714.0	2,713.0
Common Stock | Cumulative Effect, Period of Adoption, Adjusted Balance
Common Stock [Abstract]
Beginning Balance (in shares) | shares		401,000,000
Equity, Beginning Balance		$ 2,714.0
Capital Surplus - Preferred Stock
Common Stock [Abstract]
Equity, Beginning Balance		5,746.0	5,009.0
Dividends, Cash [Abstract]
Preferred stock discount accretion		2.0	2.0
Preferred stock issuance		1,487.0
Equity, Ending Balance		7,235.0	5,011.0
Capital Surplus - Preferred Stock | Cumulative Effect, Period of Adoption, Adjusted Balance
Common Stock [Abstract]
Equity, Beginning Balance		5,746.0
Capital Surplus - Common Stock and Other
Common Stock [Abstract]
Equity, Beginning Balance		12,630.0	12,448.0
Dividends, Cash [Abstract]
Treasury stock activity		70.0	45.0
Other		(71.0)	(17.0)
Equity, Ending Balance		12,629.0	12,476.0
Capital Surplus - Common Stock and Other | Cumulative Effect, Period of Adoption, Adjusted Balance
Common Stock [Abstract]
Equity, Beginning Balance		12,630.0
Retained Earnings
Common Stock [Abstract]
Equity, Beginning Balance		53,572.0	50,228.0
Net income		1,677.0	1,408.0
Dividends, Cash [Abstract]
Common		(607.0)	(531.0)
Preferred		(68.0)	(45.0)
Preferred stock discount accretion		(2.0)	(2.0)
Equity, Ending Balance		54,598.0	51,058.0
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
Common Stock [Abstract]
Equity, Beginning Balance		26.0
Retained Earnings | Cumulative Effect, Period of Adoption, Adjusted Balance
Common Stock [Abstract]
Equity, Beginning Balance		53,598.0
Accumulated Other Comprehensive Income (Loss)
Common Stock [Abstract]
Equity, Beginning Balance		(10,172.0)	409.0
Other comprehensive income (loss), net of tax		1,064.0	(6,140.0)
Dividends, Cash [Abstract]
Equity, Ending Balance		(9,108.0)	(5,731.0)
Accumulated Other Comprehensive Income (Loss) | Cumulative Effect, Period of Adoption, Adjusted Balance
Common Stock [Abstract]
Equity, Beginning Balance		(10,172.0)
Treasury Stock
Common Stock [Abstract]
Equity, Beginning Balance		(18,716.0)	(15,112.0)
Dividends, Cash [Abstract]
Treasury stock activity		(308.0)	(1,234.0)
Equity, Ending Balance		(19,024.0)	(16,346.0)
Treasury Stock | Cumulative Effect, Period of Adoption, Adjusted Balance
Common Stock [Abstract]
Equity, Beginning Balance		(18,716.0)
Non- controlling Interests
Common Stock [Abstract]
Equity, Beginning Balance		38.0	31.0
Net income		17.0	21.0
Dividends, Cash [Abstract]
Other		(25.0)	(17.0)
Equity, Ending Balance		30.0	$ 35.0
Non- controlling Interests | Cumulative Effect, Period of Adoption, Adjusted Balance
Common Stock [Abstract]
Equity, Beginning Balance		$ 38.0