Number of pending claims pertaining to a loss contingency.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118942415&loc=d3e14435-108349

Name:	us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Commitments and Contingencies (Details) $ in Millions	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jan. 19, 2018 claim
Loss Contingencies [Line Items]
Loss Contingency Accrual \| $	$ 109	$ 105
Shareholder Litigation
Loss Contingencies [Line Items]
Number of claims \| claim			5