Variable Annuity and Insurance Guarantees (Liability Rollforward) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
GMDB and GGU [Member]
Changes in Additional Liabilities for Variable Annuity and Insurance Guarantees
Balance, at the beginning of the period		$ 19	$ 17
Incurred claims		0	1
Paid claims		(2)	(1)
Balance, at the end of the period		17	17
GMIB [Member]
Changes in Additional Liabilities for Variable Annuity and Insurance Guarantees
Balance, at the beginning of the period		8	6
Incurred claims		(1)
Balance, at the end of the period		7	6
GMWB [Member]
Changes in Additional Liabilities for Variable Annuity and Insurance Guarantees
Balance, at the beginning of the period		875	463
Incurred claims	[1]	(104)	(261)
Balance, at the end of the period		771	202
GMAB [Member]
Changes in Additional Liabilities for Variable Annuity and Insurance Guarantees
Balance, at the beginning of the period		(19)	(80)
Incurred claims	[1]	(26)	4
Balance, at the end of the period		(45)	(76)
UL [Member]
Changes in Additional Liabilities for Variable Annuity and Insurance Guarantees
Balance, at the beginning of the period		659	489
Incurred claims		34	26
Paid claims		(17)	(7)
Balance, at the end of the period		$ 676	$ 508

[1] The incurred claims for GMWB and GMAB include the change in the fair value of the liabilities (contra liabilities) less paid claims.