Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Available-for-sale Debt Securities, Amortized Cost Basis	$ 20,515	$ 20,914
Variable Interest Entity, Consolidated, Carrying Amount, Assets	0	0
Marketable Securities	124	0
Available-for-sale Equity Securities, Amortized Cost Basis		$ 140
Common stock, shares authorized	1,000	1,000
Common stock, shares issued	1,000	1,000
Common stock: shares outstanding	1,000	1,000
Common stock, par value	$ 5,690	$ 5,690
Commercial Loan
Mortgage loans loss, net of allowances	$ 0	$ 0
Cash [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	0	0
Other Assets [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	0	0
Other Liabilities [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ 0	$ 0