v3.8.0.1
Investments (Allowance for Credit Losses and Recorded Investment in Commercial Mortgage and Other Loans) (Details) - USD ($)
$ in Millions
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Allowance for credit losses:      
Individually evaluated for impairment $ 7 $ 6  
Collectively evaluated for impairment 99 100  
Total ending balance 106 106 $ 112
Recorded Investment:      
Individually evaluated for impairment 116 148  
Collectively evaluated for impairment 56,035 52,737  
Total ending balance 56,151 52,885  
Commercial Mortgage Loans      
Allowance for credit losses:      
Individually evaluated for impairment 7 6  
Collectively evaluated for impairment 90 90  
Total ending balance 97 96 97
Recorded Investment:      
Individually evaluated for impairment 75 116  
Collectively evaluated for impairment 52,009 48,911  
Total ending balance 52,084 49,027  
Agricultural Property Loans      
Allowance for credit losses:      
Individually evaluated for impairment 0 0  
Collectively evaluated for impairment 3 2  
Total ending balance 3 2 2
Recorded Investment:      
Individually evaluated for impairment 39 30  
Collectively evaluated for impairment 3,164 2,928  
Total ending balance 3,203 2,958  
Residential property loans      
Allowance for credit losses:      
Individually evaluated for impairment 0 0  
Collectively evaluated for impairment 1 2  
Total ending balance 1 2 3
Recorded Investment:      
Individually evaluated for impairment 0 0  
Collectively evaluated for impairment 196 252  
Total ending balance 196 252  
Other collateralized loans      
Allowance for credit losses:      
Individually evaluated for impairment 0 0  
Collectively evaluated for impairment 0 0  
Total ending balance 0 0 0
Recorded Investment:      
Individually evaluated for impairment 0 0  
Collectively evaluated for impairment 5 10  
Total ending balance 5 10  
Uncollateralized loans      
Allowance for credit losses:      
Individually evaluated for impairment 0 0  
Collectively evaluated for impairment 5 6  
Total ending balance 5 6 $ 10
Recorded Investment:      
Individually evaluated for impairment 2 2  
Collectively evaluated for impairment 661 636  
Total ending balance $ 663 $ 638