Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Mortgage loans (net of valuation allowances of $55 and $46, respectively; includes $93 and $115, respectively, at estimated fair value, relating to variable interest entities)	$ 12,934	$ 10,640
Assets
Amortized cost of fixed maturity securities available-for-sale	59,072	58,599
Cost of equity securities available-for-sale	139	142
Mortgage loans valuation allowances	55	46
Accrued investment income relating to variable interest entities	649	575
Liabilities
Long-term debt, at estimated fair value, relating to variable interest entities	$ 237	$ 46
Equity
Common stock, par value	$ 25,000	$ 25,000
Common stock, shares authorized	4,000	4,000
Common stock, shares issued	3,000	3,000
Common stock, shares outstanding	3,000	3,000
Variable Interest Entity, Primary Beneficiary
Mortgage loans (net of valuation allowances of $55 and $46, respectively; includes $93 and $115, respectively, at estimated fair value, relating to variable interest entities)	$ 93	$ 115
Assets
Accrued investment income relating to variable interest entities	0	1
Liabilities
Long-term debt, at estimated fair value, relating to variable interest entities	$ 3	$ 11