Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Securities held to maturity, fixed maturities, fair value		$ 38,072	$ 40,021
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)		672,881	671,249
Asset derivatives		$ 331	$ 1,207
Liability derivatives		474	1,998
Consolidated Entity Excluding Variable Interest Entities (VIE)
Securities available for sale, fixed maturities, amortized cost		69,370	62,195
Securities available for sale, perpetual securities, amortized cost		1,224	1,269
Securities available for sale, equity securities, cost		240	231
Securities held to maturity, fixed maturities, fair value		38,072	40,021
Variable Interest Entity, Consolidated
Securities available for sale, fixed maturities, amortized cost		4,300	4,168
Securities available for sale, perpetual securities, amortized cost		238	237
Securities available for sale, equity securities, cost		606	972
Asset derivatives	[1]	151	127
Liability derivatives	[1]	128	146
Loan receivables and limited partnerships | Variable Interest Entity, Consolidated
Other investments held in unit trust, net of reserves, amortized cost		$ 2,341	$ 819

[1] Consists entirely of derivatives