Investments, Long-Term Receivables and Equity Investee Transactions - Summarized Financial Information of Investees Accounted for by Equity Method of Accounting (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Net sales	$ 20,275	$ 9,741	$ 12,937
Earnings (loss) before Interest and Income Taxes	4,946	(1,075)	(230)
Net earnings (loss) attributable to United States Steel Corporation	4,174	(1,165)	(630)
Current Assets	7,152	4,432
Current liabilities	3,852	2,656
Equity Method Investees
Schedule of Equity Method Investments [Line Items]
Net sales	2,229	2,485	2,528
Earnings (loss) before Interest and Income Taxes	376	12	253
Net earnings (loss) attributable to United States Steel Corporation	346	(124)	235
Current Assets	744	960	1,144
Noncurrent Assets	1,084	3,101	2,976
Current liabilities	293	419	573
Noncurrent Liabilities	$ 529	$ 3,063	$ 2,542