Derivative Financial Instruments - Net Gain (Loss) Recognized on Designated Instruments (Details) - Cash Flow Hedges - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Derivative Instruments, Gain (Loss)
Amount of loss reclassified from AOCI into income	$ 0	$ 0
Interest Rate Contracts
Derivative Instruments, Gain (Loss)
Amount of loss reclassified from AOCI into income	$ 0		$ 0

Amount before tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580

Name:	us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration