Investment Holding Level 4 Repurchase Agreements, Dollar Roll Transactions and Other (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	$ 96
Reverse Repurchase Agreements Segregated under Other Regulations		$ 0
Interest-bearing Deposit Liabilities, Domestic	2,500,000,000	2,500,000,000
Securities Held as Collateral, at Fair Value	1,500,000,000	461,000,000
Securities Received as Collateral	59,000,000	0
Securities Loaned	1,500,000,000	488,000,000
Fixed Maturities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Available-for-sale Securities Pledged as Collateral	318,000,000	226,000,000
Cash [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Available-for-sale Securities Pledged as Collateral		22,000,000
Other Liabilities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	313,000,000	241,000,000
US Treasury Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Available-for-sale Securities Pledged as Collateral	$ 104,000,000	$ 102,000,000