Face (par) amount of debt instrument at time of issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Debt - Senior Notes (Details) - USD ($)	Dec. 31, 2019	Jan. 31, 2018	Mar. 31, 2012
Debt Instrument [Line Items]
Amortizing loan facility		$ 800,000,000	$ 1,000,000,000.0
Senior Notes \| Senior Notes Payable in 2024
Debt Instrument [Line Items]
Stated interest rate	4.125%
Senior Notes \| Senior Notes due in 2022
Debt Instrument [Line Items]
Stated interest rate	4.875%
Senior Notes \| Senior Notes due in 2021
Debt Instrument [Line Items]
Stated interest rate	4.75%