Total Equity and Other Comprehensive Income (Rollforward of Total Equity) (Details) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
	Apr. 26, 2022 $ / shares shares	Jun. 30, 2022 USD ($) shares	Jun. 30, 2021 USD ($) shares	Jun. 30, 2022 USD ($) shares	Jun. 30, 2021 USD ($) shares	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Common Stock [Abstract]
Equity, Beginning Balance		$ 49,216.0	$ 53,879.0	$ 55,726.0	$ 54,041.0
Net income		1,496.0	1,103.0	2,925.0	2,929.0
Other comprehensive income (loss), net of tax		(2,627.0)	173.0	(8,767.0)	(1,307.0)
Dividends, Cash [Abstract]
Common		(626.0)	(492.0)	(1,157.0)	(985.0)
Preferred		(71.0)	(48.0)	(116.0)	(105.0)
Preferred stock discount accretion
Preferred stock issuance		992.0		992.0
Common stock activity		15.0	12.0	15.0	12.0
Treasury stock activity		(725.0)	10.0	(1,914.0)	138.0
Other		18.0	48.0	(16.0)	(38.0)
Equity, Ending Balance		47,688.0	54,685.0	47,688.0	54,685.0
Preferred stock, par value		$ 0.5	$ 0.5	$ 0.5	$ 0.5	$ 0.5	$ 0.5	$ 0.5	$ 0.5
Series U Preferred Stock
Dividends, Cash [Abstract]
Depositary shares issued (shares) | shares	1,000,000
Depositary shares conversion ratio	0.01
Fixed interest rate	6.00%
Preferred stock, par or stated value per share (in dollars per share) | $ / shares	$ 1
Common Stock
Common Stock [Abstract]
Beginning Balance (in shares) | shares		415,000,000	425,000,000	420,000,000	424,000,000
Treasury stock activity, shares | shares		(4,000,000)		(9,000,000)	1,000,000
Ending Balance, (in shares) | shares		411,000,000	425,000,000	411,000,000	425,000,000
Equity, Beginning Balance		$ 2,713.0	$ 2,713.0	$ 2,713.0	$ 2,713.0
Dividends, Cash [Abstract]
Common stock activity		1.0		1.0
Equity, Ending Balance		2,714.0	2,713.0	2,714.0	2,713.0
Capital Surplus - Preferred Stock
Common Stock [Abstract]
Equity, Beginning Balance		5,011.0	3,518.0	5,009.0	3,517.0
Dividends, Cash [Abstract]
Preferred stock discount accretion		1.0	1.0	3.0	2.0
Preferred stock issuance		992.0		992.0
Equity, Ending Balance		6,004.0	3,519.0	6,004.0	3,519.0
Capital Surplus - Common Stock and Other
Common Stock [Abstract]
Equity, Beginning Balance		12,476.0	12,361.0	12,448.0	12,367.0
Dividends, Cash [Abstract]
Common stock activity		14.0	12.0	14.0	12.0
Treasury stock activity		5.0	4.0	50.0	73.0
Other		32.0	32.0	15.0	(43.0)
Equity, Ending Balance		12,527.0	12,409.0	12,527.0	12,409.0
Retained Earnings
Common Stock [Abstract]
Equity, Beginning Balance		51,058.0	48,113.0	50,228.0	46,848.0
Net income		1,481.0	1,091.0	2,889.0	2,907.0
Dividends, Cash [Abstract]
Common		(626.0)	(492.0)	(1,157.0)	(985.0)
Preferred		(71.0)	(48.0)	(116.0)	(105.0)
Preferred stock discount accretion		(1.0)	(1.0)	(3.0)	(2.0)
Equity, Ending Balance		51,841.0	48,663.0	51,841.0	48,663.0
Accumulated Other Comprehensive Income (Loss)
Common Stock [Abstract]
Equity, Beginning Balance		(5,731.0)	1,290.0	409.0	2,770.0
Other comprehensive income (loss), net of tax		(2,627.0)	173.0	(8,767.0)	(1,307.0)
Dividends, Cash [Abstract]
Equity, Ending Balance		(8,358.0)	1,463.0	(8,358.0)	1,463.0
Treasury Stock
Common Stock [Abstract]
Equity, Beginning Balance		(16,346.0)	(14,146.0)	(15,112.0)	(14,205.0)
Dividends, Cash [Abstract]
Treasury stock activity		(730.0)	6.0	(1,964.0)	65.0
Equity, Ending Balance		(17,076.0)	(14,140.0)	(17,076.0)	(14,140.0)
Non- controlling Interests
Common Stock [Abstract]
Equity, Beginning Balance		35.0	30.0	31.0	31.0
Net income		15.0	12.0	36.0	22.0
Dividends, Cash [Abstract]
Other		(14.0)	16.0	(31.0)	5.0
Equity, Ending Balance		$ 36.0	$ 58.0	$ 36.0	$ 58.0