Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Securities held to maturity, fixed maturities, fair value	$ 37,520	$ 38,497
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	1,900,000	1,900,000
Common stock, shares issued (in shares)	669,723	668,132
Asset derivatives	$ 676	$ 802
Liability derivatives	371	2,423
Investments Other Than Consolidated Variable Interest Entities
Securities available for sale, fixed maturities, amortized cost	56,903	55,365
Securities available for sale, perpetual securities, amortized cost	1,586	2,035
Securities available for sale, equity securities, cost	117	19
Securities held to maturity, fixed maturities, fair value	37,520	38,413
Variable Interest Entity, Consolidated
Securities available for sale, fixed maturities, amortized cost	3,739	3,020
Securities available for sale, perpetual securities, amortized cost	255	405
Securities available for sale, equity securities, cost	363	0
Securities held to maturity, fixed maturities, fair value	0	84
Asset derivatives	102	106
Liability derivatives	$ 293	$ 318