Employee Benefit Arrangements - Net Actuarial (Gains) Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net (gain) loss recognition	$ (50)	$ (14)	$ (57)
Discount Rate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net (gain) loss recognition	160	(196)	(69)
Asset Returns
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net (gain) loss recognition	(207)	142	(24)
Mortality Table Assumptions
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net (gain) loss recognition	6	14	22
Demographic Data and other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net (gain) loss recognition	$ (9)	$ 25	$ 13