Segment Information - Disaggregation of Revenue by Major End Market Served (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue, Major Customer [Line Items]
Sales:	$ 1,253	$ 1,818	$ 2,887	$ 3,570
Operating Segments
Revenue, Major Customer [Line Items]
Sales:	1,253	1,822	2,885	3,578
Engine Products
Revenue, Major Customer [Line Items]
Sales:	585	835	1,366	1,648
Engine Products | Operating Segments
Revenue, Major Customer [Line Items]
Sales:	585	835	1,366	1,648
Engineered Structures
Revenue, Major Customer [Line Items]
Sales:	229	331	504	625
Engineered Structures | Operating Segments
Revenue, Major Customer [Line Items]
Sales:	229	331	504	625
Fastening Systems
Revenue, Major Customer [Line Items]
Sales:	326	399	711	794
Fastening Systems | Operating Segments
Revenue, Major Customer [Line Items]
Sales:	326	399	711	794
Forged Wheels
Revenue, Major Customer [Line Items]
Sales:	113	257	304	511
Forged Wheels | Operating Segments
Revenue, Major Customer [Line Items]
Sales:	113	257	304	511
Aerospace | Operating Segments
Revenue, Major Customer [Line Items]
Sales:	908	1,283	2,097	2,533
Aerospace | Engine Products
Revenue, Major Customer [Line Items]
Sales:	437	676	1,071	1,348
Aerospace | Engineered Structures
Revenue, Major Customer [Line Items]
Sales:	208	303	462	575
Aerospace | Fastening Systems
Revenue, Major Customer [Line Items]
Sales:	263	304	564	610
Aerospace | Forged Wheels
Revenue, Major Customer [Line Items]
Sales:	0	0	0	0
Commercial Transportation | Operating Segments
Revenue, Major Customer [Line Items]
Sales:	148	324	384	645
Commercial Transportation | Engine Products
Revenue, Major Customer [Line Items]
Sales:	0	5	0	12
Commercial Transportation | Engineered Structures
Revenue, Major Customer [Line Items]
Sales:	0	0	0	0
Commercial Transportation | Fastening Systems
Revenue, Major Customer [Line Items]
Sales:	35	62	80	120
Commercial Transportation | Forged Wheels
Revenue, Major Customer [Line Items]
Sales:	113	257	304	513
Industrial and Other | Operating Segments
Revenue, Major Customer [Line Items]
Sales:	197	215	404	400
Industrial and Other | Engine Products
Revenue, Major Customer [Line Items]
Sales:	148	154	295	288
Industrial and Other | Engineered Structures
Revenue, Major Customer [Line Items]
Sales:	21	28	42	50
Industrial and Other | Fastening Systems
Revenue, Major Customer [Line Items]
Sales:	28	33	67	64
Industrial and Other | Forged Wheels
Revenue, Major Customer [Line Items]
Sales:	$ 0	$ 0	$ 0	$ (2)