Investments - Realized Gains and Losses and Proceeds on Investments and Other Assets (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Valuation of fixed maturity securities available for sale
Allowance for Credit Loss	$ (11,000,000)		$ 0
Impairment of lease assets
Net Realized Gains (Losses)		$ (4,000,000)
Gross Proceeds from Sale/Maturity		0
Other realized gains and losses, net
Net Realized Gains (Losses)	(10,000,000)
Gross Proceeds from Sale/Maturity	9,000,000
Total
Net Realized Gains (Losses)	(320,000,000)	142,000,000
Gross Proceeds from Sale/Maturity	269,000,000	300,000,000
Sales and maturities of fixed maturity securities available for sale
Sales and maturities of fixed maturity securities available for sale
Gross Realized Gains	12,000,000	1,000,000
Gross Realized Losses	(1,000,000)	(1,000,000)
Net Realized Gains (Losses)	11,000,000	0
Gross Proceeds from Sale/Maturity	177,000,000	235,000,000
Preferred securities
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Gross Realized Gains	0	0
Gross Realized Losses	0	0
Net Realized Gains (Losses)	0	0
Gross Proceeds from Sale/Maturity	83,000,000	24,000,000
Valuation Of Equity And Preferred Securities
Net Realized Gains (Losses)	(42,000,000)	11,000,000
Equity securities
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Gross Realized Gains	0	4,000,000
Gross Realized Losses	0	0
Net Realized Gains (Losses)	0	4,000,000
Gross Proceeds from Sale/Maturity	0	41,000,000
Valuation Of Equity And Preferred Securities
Net Realized Gains (Losses)	(205,000,000)	126,000,000
Other long-term investments
Valuation of other long term investments
Net Realized Gains (Losses)	$ (63,000,000)	$ 5,000,000