Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Preferred stock, par value	$ 1	$ 1
Preferred stock, authorized shares	10,000,000	10,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value	$ 1	$ 1
Common stock, authorized shares	400,000,000	400,000,000
Common stock, issued shares	283,433,401	283,625,689
Accumulated other comprehensive income (loss), taxes	$ 8	$ 8
Treasury stock, shares	204,000,108	193,803,976
Non Variable Interest Entity [Member]
Fixed-maturity securities held as available-for-sale, amortized cost	$ 2,705	$ 3,601
Investments pledged as collateral, amortized cost	15	46
Short-term investments, amortized cost	423	241
Medium-term notes, financial instruments carried at fair value	108	102
Variable Interest Entity Primary Beneficiary [Member]
Investments held-to-maturity, fair value	892	925
Variable interest entity notes, financial instruments carried at fair value	$ 403	$ 480