Changes in Accumulated Other Comprehensive Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at January 1	$ 139,940	$ 132,726	$ 145,208
Components of Other Comprehensive Income (Loss):
Other Comprehensive Gain (Loss), Net of Tax	1,091	1,723	(622)
Balance at December 31	160,242	139,940	132,726
Income tax expense (benefit)	14,066	5,950	(1,892)
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at January 1	(3,889)	(5,612)	(4,990)
Components of Other Comprehensive Income (Loss):
Before Reclassifications	729	887	(1,454)
Reclassifications	362	836	832
Other Comprehensive Gain (Loss), Net of Tax	1,091	1,723	(622)
Balance at December 31	(2,798)	(3,889)	(5,612)
Currency Translation Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at January 1	(162)	(107)	(142)
Components of Other Comprehensive Income (Loss):
Before Reclassifications	(41)	(55)	35
Reclassifications	0	0	0
Other Comprehensive Gain (Loss), Net of Tax	(41)	(55)	35
Balance at December 31	(203)	(162)	(107)
Unrealized Holding Gains (Losses) on Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at January 1	(11)	(10)	(8)
Components of Other Comprehensive Income (Loss):
Before Reclassifications	(1)	(1)	(2)
Reclassifications	0	0	0
Other Comprehensive Gain (Loss), Net of Tax	(1)	(1)	(2)
Balance at December 31	(12)	(11)	(10)
Derivatives
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at January 1	0	0	0
Components of Other Comprehensive Income (Loss):
Before Reclassifications	68	(6)	0
Reclassifications	(80)	6	0
Other Comprehensive Gain (Loss), Net of Tax	(12)	0	0
Balance at December 31	(12)	0	0
Defined Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at January 1	(3,716)	(5,495)	(4,840)
Components of Other Comprehensive Income (Loss):
Before Reclassifications	703	949	(1,487)
Reclassifications	442	830	832
Other Comprehensive Gain (Loss), Net of Tax	1,145	1,779	(655)
Balance at December 31	(2,571)	$ (3,716)	$ (5,495)
Defined Benefit Plans | Reclassification out of Accumulated Other Comprehensive Income
Components of Other Comprehensive Income (Loss):
Reclassification, before tax amount	580
Income tax expense (benefit)	$ 138