Information on Business Segments - Additional Information (Details) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2021 USD ($) $ / shares	Dec. 31, 2021 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) retiree	Dec. 31, 2021 USD ($) $ / shares	Aug. 03, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of business segments		4		4
Equity method investments	$ 689	$ 689	$ 689	$ 689	$ 689		$ 784
Non-cash, non-operating pension settlement charge	1,700		1,700
Non-cash, non-operating pension settlement charge, after tax	$ 1,300		$ 1,300
Non-cash, non-operating pension settlement charge, per share, after tax (in dollars per share) | $ / shares	$ 4.72				$ 4.72
Outstanding pension benefit obligations and related plan assets						$ 4,900