Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance, Beginning Balance	$ 181	$ 227	$ 133
Valuation Allowances and Reserves, Charged to Cost and Expense	56	(34)	89
Valuation Allowances and Reserves, Charged to Other Accounts	1	(12)	(11)
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	0	0	6
Valuation Allowances and Reserves, Balance, Ending Balance	236	181	227
SEC Schedule, 12-09, Allowance, Loan and Lease Loss, Real Estate [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance, Beginning Balance	11	9	8
Valuation Allowances and Reserves, Charged to Cost and Expense	1	2	1
Valuation Allowances and Reserves, Charged to Other Accounts	0	0	0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	0	0	0
Valuation Allowances and Reserves, Balance, Ending Balance	$ 12	$ 11	$ 9