Business Dispositions and Discontinued Operations - Major Classes of Assets and Liabilities Transferred by the Company to the Buyer in Connection with Sale (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	May 31, 2018	Dec. 31, 2017	May 10, 2017
Liabilities
Long-term debt	$ 4,348	$ 4,265
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Assets
Cash and investments			$ 27,058	$ 30,135
Reinsurance recoverables			20,718	20,785
Loss accrual			(3,044)	(3,257)
Other assets			2,907	1,439
Separate account assets			110,773	115,834
Assets			158,412	164,936
Liabilities
Reserve for future policy benefits and unpaid loss and loss adjustment expenses			14,308	14,482
Other policyholder funds and benefits payable			28,680	29,228
Long-term debt			142	142
Other liabilities			2,222	2,756
Separate account liabilities			110,773	115,834
Liabilities			$ 156,125	$ 162,442
Disposal Group, Disposed of by Sale, Not Discontinued Operations | P&C Runoff Subsidiaries
Assets
Cash and investments					$ 669
Reinsurance recoverables					268
Assets					937
Liabilities
Reserve for future policy benefits and unpaid loss and loss adjustment expenses					653
Other liabilities					12
Liabilities					$ 665