Scheduled Maturity Distribution of Fixed Maturity Securities (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Amortized cost or cost
Due one year or less	$ 2,135
Due after one year through five years	10,474
Due after five years through ten years	11,824
Due after ten years	21,229
Subtotal	45,662
Amortized cost or cost, fixed maturity securities	56,807	$ 55,854
Fair value
Due one year or less	2,147
Due after one year through five years	10,950
Due after five years through ten years	12,155
Due after ten years	23,955
Subtotal	49,207
Fair value, fixed maturity securities	60,851	$ 61,276
Residential mortgage-backed
Amortized cost or cost
Fixed maturity securities	4,728
Fair value
Fixed maturity securities	5,118
Commercial mortgage-backed
Amortized cost or cost
Fixed maturity securities	2,464
Fair value
Fixed maturity securities	2,587
Other asset-backed
Amortized cost or cost
Fixed maturity securities	3,953
Fair value
Fixed maturity securities	$ 3,939