Segment Information - Results of Segment Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net sales	$ 20,275	$ 9,741	$ 12,937
Earnings (loss) from investees	170	(117)	79
Earnings (loss) before Interest and Income Taxes	4,946	(1,075)	(230)
Depreciation, depletion & amortization	791	643	616
Capital expenditures	863	725	1,252
Flat-Rolled
Segment Reporting Information [Line Items]
Net sales	12,180	7,071	9,279
Mini Mill (a)
Segment Reporting Information [Line Items]
Net sales	3,008
USSE
Segment Reporting Information [Line Items]
Net sales	4,262	1,967	2,417
Tubular
Segment Reporting Information [Line Items]
Net sales	789	639	1,188
Total reportable segments
Segment Reporting Information [Line Items]
Net sales	20,239	9,677	12,884
Other
Segment Reporting Information [Line Items]
Net sales	36	64	53
Operating Segments
Segment Reporting Information [Line Items]
Net sales		(316)	(402)
Operating Segments | Flat-Rolled
Segment Reporting Information [Line Items]
Net sales	12,358	7,279	9,560
Earnings (loss) from investees	150	(9)	84
Earnings (loss) before Interest and Income Taxes	2,630	(596)	196
Depreciation, depletion & amortization	491	496	456
Capital expenditures	422	484	943
Operating Segments | Mini Mill (a)
Segment Reporting Information [Line Items]
Net sales	3,516
Earnings (loss) from investees	0
Earnings (loss) before Interest and Income Taxes	1,206
Depreciation, depletion & amortization	151
Capital expenditures	331
Operating Segments | Mini Mill #2
Segment Reporting Information [Line Items]
Capital expenditures	144
Operating Segments | USSE
Segment Reporting Information [Line Items]
Net sales	4,266	1,970	2,420
Earnings (loss) from investees	0	0	0
Earnings (loss) before Interest and Income Taxes	975	9	(57)
Depreciation, depletion & amortization	98	97	92
Capital expenditures	57	79	153
Operating Segments | Tubular
Segment Reporting Information [Line Items]
Net sales	809	646	1,191
Earnings (loss) from investees	14	4	5
Earnings (loss) before Interest and Income Taxes	1	(179)	(67)
Depreciation, depletion & amortization	46	39	46
Capital expenditures	51	159	145
Operating Segments | Total reportable segments
Segment Reporting Information [Line Items]
Net sales	20,949	9,895	13,171
Earnings (loss) from investees	164	(5)	89
Earnings (loss) before Interest and Income Taxes	4,812	(766)	72
Depreciation, depletion & amortization	786	632	594
Capital expenditures	861	722	1,241
Operating Segments | Other
Segment Reporting Information [Line Items]
Net sales	101	162	168
Earnings (loss) from investees	6	(94)	(10)
Earnings (loss) before Interest and Income Taxes	(11)	(39)	23
Depreciation, depletion & amortization	5	11	22
Capital expenditures	2	3	11
Intersegment Sales
Segment Reporting Information [Line Items]
Net sales	(775)	(316)	(402)
Intersegment Sales | Flat-Rolled
Segment Reporting Information [Line Items]
Net sales	178	208	281
Intersegment Sales | Mini Mill (a)
Segment Reporting Information [Line Items]
Net sales	508
Intersegment Sales | USSE
Segment Reporting Information [Line Items]
Net sales	4	3	3
Intersegment Sales | Tubular
Segment Reporting Information [Line Items]
Net sales	20	7	3
Intersegment Sales | Total reportable segments
Segment Reporting Information [Line Items]
Net sales	710	218	287
Intersegment Sales | Other
Segment Reporting Information [Line Items]
Net sales	65	98	115
Reconciling Items and Eliminations
Segment Reporting Information [Line Items]
Net sales	(775)
Earnings (loss) from investees	0	(18)	0
Earnings (loss) before Interest and Income Taxes	145	(270)	(325)
Depreciation, depletion & amortization	0	0	0
Capital expenditures	$ 0	$ 0	$ 0