CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income		$ 409	$ 208	$ 905	$ 593
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	[1]	(52)	32	(24)	(26)
Fixed price diesel swaps		0	1	1	(2)
Other comprehensive income (loss)		(52)	33	(23)	(28)
Comprehensive income (loss)	[1]	$ 357	$ 241	$ 882	$ 565

[1] There were no material reclassifications from accumulated other comprehensive loss reflected in other comprehensive income (loss) during 2021 or 2020. There was no material tax impact related to the foreign currency translation adjustments. We have historically considered the undistributed earnings of our foreign subsidiaries to be indefinitely reinvested, and, accordingly, no taxes were provided on such earnings prior to the fourth quarter of 2020. In the fourth quarter of 2020, we identified $135 of cash in our foreign operations in excess of near-term working capital needs, and determined that this amount could no longer be considered indefinitely reinvested. As a result, our prior assertion that all undistributed earnings of our foreign subsidiaries should be considered indefinitely reinvested changed. We continue to expect that the remaining balance of our undistributed foreign earnings will be indefinitely reinvested. If we determine that all or a portion of such foreign earnings are no longer indefinitely reinvested, we may be subject to additional foreign withholding taxes and U.S. state income taxes. There were no material taxes associated with other comprehensive income (loss) during 2021 or 2020.