Leases - Additional Information (Details) - USD ($) $ in Billions	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019
Leases [Abstract]
Finance Lease, Right-of-Use Asset	$ 58.0	$ 57.4
Finance Lease, Right-of-Use-Asset, Accumulated Amortization	$ 30.5		$ 30.0

Amount of lessee's right to use underlying asset under finance lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

Name:	us-gaap_FinanceLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant