Summary of Accounting Policies - Pre-production Design and Development and Tooling Assets (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Unbilled pre-production design and development costs	$ 25	$ 22
Original Equipment tools and dies, owned	72	62
In-process tools and dies built for original equipment customers	$ 117	$ 97

In ProcessTools and Dies Built For Original Equipment Customer

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant