Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for doubtful accounts
Valuation and qualifying accounts
Balance at Beginning of Period	$ 822	$ 788	$ 668
Charged to Costs and Expenses	56	37	126
Charged to Other Accounts	(11)	(3)	(6)
Deductions	0	0	0
Balance at End of Period	867	822	788
Valuation allowance and reserves, current	46	42	22
Environmental, litigation, tax and other reserves
Valuation and qualifying accounts
Balance at Beginning of Period	2,429	2,411	994
Charged to Costs and Expenses	900	115	182
Charged to Other Accounts	94	43	1,408
Deductions	(259)	(140)	(173)
Balance at End of Period	3,164	2,429	2,411
Environmental litigation tax and other reserves, current	$ 790	$ 149	$ 188