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Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Fixed-maturity securities held as available-for-sale, amortized cost | $ 4,438 | $ 5,450
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 | 283,717,973 | 283,989,999
Accumulated other comprehensive income (loss), taxes | $ 0 | $ 4
Accumulated other comprehensive income (loss), taxes | $ 16 | $ 37
Treasury stock, shares | 192,233,526 | 148,789,168
Non Variable Interest Entity [Member] |  |
Fixed-maturity securities held as available-for-sale, amortized cost | $ 3,728 | $ 4,713
Investments pledged as collateral, amortized cost | 147 | 234
Short-term investments held as available-for-sale, amortized cost | 589 | 552
Other investments, fair value | 4 | 5
Medium-term notes, financial instruments carried at fair value | 115 | 101
Variable Interest Entity Primary Beneficiary [Member] |  |
Investments held-to-maturity, fair value | 916 | 876
Variable interest entity notes, financial instruments carried at fair value | $ 1,069 | $ 1,351

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