Leases - Disclosures Related to Prior Periods (Details) $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)
Leases [Abstract]
Rent expense under operating lease	$ 16
Operating Leases
2019	13
2020	11
2021	9
2022	6
2023	4
Thereafter	40
Total	83
Capital Leases
2019	1
2020	2
2021	1
2022	1
2023	1
Thereafter	7
Total	13
Less: Amounts representing interest	3
Present value of minimum lease payments	10
Less: Current portion of capital leases	1
Long-term portion of capital leases	$ 9

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84164817&loc=d3e45280-112737