Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Securities held to maturity, fixed maturities, fair value	$ 42,807	$ 37,520
Common stock, par value (in dollars per share)	$ 0.1	$ 0.1
Common stock, shares authorized (in shares)	1,900,000,000	1,900,000,000
Common stock, shares issued (in shares)	670,401,000	669,723,000
Asset derivatives	$ 1,144	$ 676
Liability derivatives	332	371
Investments Other Than Consolidated Variable Interest Entities
Securities available for sale, fixed maturities, amortized cost	60,538	56,903
Securities available for sale, perpetual securities, amortized cost	1,695	1,586
Securities available for sale, equity securities, cost	192	117
Securities held to maturity, fixed maturities, fair value	42,807	37,520
Variable Interest Entity, Consolidated
Securities available for sale, fixed maturities, amortized cost	4,110	3,739
Securities available for sale, perpetual securities, amortized cost	244	255
Securities available for sale, equity securities, cost	683	363
Asset derivatives	114	102
Liability derivatives	$ 175	$ 293