Subsequent Events (Details) - Five And One Over Two Senior Notes [Member] - Senior Notes [Member] - USD ($) $ in Millions	Oct. 01, 2019	Sep. 30, 2019
Subsequent Event [Line Items]
Debt Instrument, Face Amount		$ 75
Debt Instrument, Repurchase Amount		$ 407
Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 75
Debt Instrument, Repurchase Amount	$ 76

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