Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Components of accumulated other comprehensive loss
Beginning balance	$ 3,887	$ 1,534
Reclassifications into earnings (net of tax effect)	59	78
Reclassifications into earnings, tax effect	(18)	(23)
Ending balance	2,991	482
Accumulated Other Comprehensive Income
Components of accumulated other comprehensive loss
Beginning balance	(7,130)	(9,038)
Beginning balance, tax effect	1,184	1,764
Ending balance	(7,071)	(8,960)
Ending balance, tax effect	1,166	1,741
Pension and Other Benefit Liabilities
Components of accumulated other comprehensive loss
Beginning balance	(7,170)	(9,078)
Reclassifications into earnings (net of tax effect)	59	78
Ending balance	(7,111)	(9,000)
Other
Components of accumulated other comprehensive loss
Beginning balance	40	40
Reclassifications into earnings (net of tax effect)	0	0
Ending balance	$ 40	$ 40