Debt Debt Redemption (Details) - Unsecured Debt - Senior Notes Due 2026	Oct. 04, 2018
2021
Debt Instrument [Line Items]
Redemption Price	104.406%
2022
Debt Instrument [Line Items]
Redemption Price	102.938%
2023
Debt Instrument [Line Items]
Redemption Price	101.469%
2024 and thereafter
Debt Instrument [Line Items]
Redemption Price	100.00%

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration