Special Charges (Credits) - Components of Special Charges (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Other Income and Expenses [Abstract]
(Gains) losses on sale of assets and other special charges	$ 14	$ (8)
Total operating special charges (credits)	14	(8)
Nonoperating unrealized gains on investments, net	(24)	0
Nonoperating debt extinguishment and modification fees	0	7
Total nonoperating special charges and unrealized gains on investments, net	(24)	7
Total operating and nonoperating special charges (credits) and unrealized gains on investments, net	(10)	(1)
Income tax benefit, net of valuation allowance	(3)	0
Total operating and nonoperating special charges (credits) and unrealized gains on investments, net of income taxes	$ (13)	$ (1)