Employee Benefit Plans - Schedule of Fair Value of Plan Assets Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	$ 101	$ 89
Corporate bonds (S&P rating of A or higher)
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	16	15
Corporate bonds (S&P rating of lower than A)
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	35	29
Government securities
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	33	31
Mortgage-backed securities
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	12	11
Municipal bonds
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	1	1
Money market fund
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	4	2
Common collective trusts
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	151	143
Total plan assets, at fair value
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	252	232
Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	101	89
Level 2 | Corporate bonds (S&P rating of A or higher)
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	16	15
Level 2 | Corporate bonds (S&P rating of lower than A)
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	35	29
Level 2 | Government securities
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	33	31
Level 2 | Mortgage-backed securities
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	12	11
Level 2 | Municipal bonds
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	1	1
Level 2 | Money market fund
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	$ 4	$ 2