Supplemental Cash Flow Information - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Oct. 31, 2019
Net cash (used in) provided by operating activities included:
Interest and other financial costs paid (net of amount capitalized)	$ (319)	$ (248)	$ (151)
Income taxes (paid) refunded	(75)	45	38
Non-cash investing and financing activities:
Change in accrued capital expenditures	40	(121)	(70)
U. S. Steel common stock issued for employee/non-employee director stock plans	28	19	19
Capital expenditures funded by finance lease borrowings	18	31	46
Export Credit Agreement (ECA) financing	23	34	0
Big River Steel put and call options (a)	$ 0	$ 0	$ 21
Big River Steel
Business Acquisition [Line Items]
Ownership interest				49.90%