Investments (EITF info-Number of securities and unrealized losses) (Details) $ in Millions	Jun. 30, 2020 USD ($) item		Dec. 31, 2019 USD ($) item
Number of Securities
Less than 12 months | item	142		78
12 months or more | item	21		53
Total | item	163		131
Unrealized Losses
Less than 12 months | $	$ (85)		$ (3)
12 months or more | $	(9)		(11)
Total | $	$ (94)	[1]	$ (14)
investmentgradeAFSsecuritieswithgrossunrealizedlosses	64.00%
Corporate debt securities [Member]
Number of Securities
Less than 12 months | item	60		15
12 months or more | item	3		7
Total | item	63		22
Unrealized Losses
Less than 12 months | $	$ (39)		$ 0
12 months or more | $	(7)		(2)
Total | $	$ (46)	[1]	$ (2)
Residential mortgage backed securities [Member]
Number of Securities
Less than 12 months | item	29		29
12 months or more | item	6		20
Total | item	35		49
Unrealized Losses
Less than 12 months | $	$ (2)		$ (1)
12 months or more | $	0		(3)
Total | $	$ (2)		$ (4)
Commercial mortgage backed securities [Member]
Number of Securities
Less than 12 months | item	24		18
12 months or more | item	1		7
Total | item	25		25
Unrealized Losses
Less than 12 months | $	$ (10)		$ (1)
12 months or more | $	0		(2)
Total | $	$ (10)		$ (3)
State and municipal obligations [Member]
Number of Securities
Less than 12 months | item	4		5
12 months or more | item	1		3
Total | item	5		8
Unrealized Losses
Less than 12 months | $	$ (2)		$ 0
12 months or more | $	0		(2)
Total | $	$ (2)		$ (2)
Asset backed securities [Member]
Number of Securities
Less than 12 months | item	21		10
12 months or more | item	1		6
Total | item	22		16
Unrealized Losses
Less than 12 months | $	$ (31)		$ (1)
12 months or more | $	(1)		0
Total | $	$ (32)		$ (1)
Foreign government bonds and obligations [Member]
Number of Securities
Less than 12 months | item	4		1
12 months or more | item	9		10
Total | item	13		11
Unrealized Losses
Less than 12 months | $	$ (1)		$ 0
12 months or more | $	(1)		(2)
Total | $	$ (2)		$ (2)

[1] The portion of unrealized losses due to credit-related factors is recorded in the allowance for credit losses.