Restructuring and Other Charges - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	$ 8	$ 22	$ 22	$ 166
Settlements	3	3	9	67
Accelerated depreciation		2		2
Benefit from termination of deferred benefit plan		3		3
Layoff costs	0	17	2	93
Impairment of assets to be disposed of				5
Gain on sale of assets				2
Pension benefits
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	3	8	9	10
Settlements	3	8	9	72
Other postretirement benefits
Restructuring Cost and Reserve [Line Items]
Curtailments	$ 0	2	0	2
Layoff costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges		$ 17	$ 10
Facility closing
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges				5
Facility closing | U.K. Forging Business
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges				6
Reversal of prior period programs
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges				$ 10