Statutory Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statutory Accounting Practices [Line Items]
Dividends available to be paid	$ 6,500
Approximate increase in statutory capital and surplus resulting from discount of certain A&E liabilities	147	$ 160
Minimum statutory capital and surplus required to satisfy regulatory requirements	26,300	24,200
Statutory Accounting Practices, Permitted Practice, Amount	54	178
PropertyAndCasualtySubsidiaries [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	43,684	40,780
Statutory net income	5,931	7,521	$ 8,178
LifeSubsidiaries [Member] [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	1,900	1,279
Statutory net income	$ (227)	$ (102)	$ 49