Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Fixed maturities, available-for-sale, at fair value (amortized cost of $35,913 and $35,612)	$ 35,913	$ 35,612
Equity securities, available-for-sale, at fair value (cost of $0 and $907)	0	907
Mortgage loans (net of allowances for loan losses of $1 and $1)	$ 1	$ 1
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,500,000,000	1,500,000,000
Common stock, $0.01 par value — 1,500,000,000 shares authorized, 384,923,222 and 384,923,222 shares issued	384,923,222.00	384,923,222.00
Treasury stock, at cost — 26,563,921 and 28,088,186 shares	26,563,921	28,088,186