Schedule V - Valuation and Qualifying Accounts (Details) - SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	$ 74	$ 63	$ 52	$ 96
SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Cost and Expense	11	31	9
SEC Schedule, 12-09, Valuation Allowances and Reserves, Business Acquired	0	0	0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	$ 0	$ (20)	$ (53)