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
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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

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Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Period Type:	duration

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

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Debt - Senior Notes (Details) - USD ($)	3 Months Ended	12 Months Ended
Debt - Senior Notes (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 20, 2019
Debt Instrument [Line Items]
Repayments of long-term debt		$ 901,900,000	$ 552,000,000.0	$ 302,300,000
Senior Notes
Debt Instrument [Line Items]
Repayments of long-term debt	$ 300,000,000
Senior Notes Due 2026
Debt Instrument [Line Items]
Aggregate principal amount					$ 500,000,000
Senior Notes Due 2026 \| Senior Notes
Debt Instrument [Line Items]
Interest rate percentage					3.20%
Senior Notes Due 2029
Debt Instrument [Line Items]
Aggregate principal amount					$ 500,000,000
Senior Notes Due 2029 \| Senior Notes
Debt Instrument [Line Items]
Interest rate percentage					3.45%
Senior Notes Due 2049
Debt Instrument [Line Items]
Aggregate principal amount					$ 500,000,000
Senior Notes Due 2049 \| Senior Notes
Debt Instrument [Line Items]
Interest rate percentage					4.50%