Employee Benefit Plans - Fair values of pension plan assets (Details) (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Net payables related to security transactions	$ 9	$ 16
Insurance Contract Rights And Obligations Fair Value Option [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Participating Interest In Annuity Contract	$ 95	$ 84

Amount payable to other broker-dealer and clearing organization, including, but not limited to, security failed-to-receive, deposit received for security loaned, open transaction, and floor-brokerage payable.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

Name:	srt_PayablesToBrokerDealersAndClearingOrganizations
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant