Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions		Jun. 30, 2017	Dec. 31, 2016
Securities held to maturity, fixed maturities, fair value		$ 39,307	$ 40,021
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)		672,037,000	671,249,000
Asset derivatives		$ 543	$ 1,207
Liability derivatives		1,121	1,998
Variable Interest Entity, Consolidated
Securities available for sale, fixed maturities, amortized cost		4,149	4,168
Securities available for sale, perpetual securities, amortized cost		241	237
Securities available for sale, equity securities, cost		1,032	972
Asset derivatives	[1]	142	127
Liability derivatives	[1]	133	146
Investments Other Than Consolidated Variable Interest Entities
Securities available for sale, fixed maturities, amortized cost		67,809	62,195
Securities available for sale, perpetual securities, amortized cost		1,319	1,269
Securities available for sale, equity securities, cost		257	231
Securities held to maturity, fixed maturities, fair value		39,307	40,021
Commercial mortgage and middle market loans | Variable Interest Entity, Consolidated
Other investments held in unit trust, net of reserves, amortized cost		$ 1,200	$ 819

[1] Consist entirely of derivatives