Amount, after tax, of accumulated gain (loss) on derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

Name:	us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Derivative Financial Instruments (Financial Statement Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	$ (259)		$ (243)
Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	$ 259	$ 262