Investments and Cash - Distribution of Fixed-Maturity Securities by Contractual Maturity (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Amortized Cost
Due within one year	$ 146
Due after one year through five years	1,906
Due after five years through 10 years	2,225
Due after 10 years	3,647
Estimated Fair Value
Due within one year	148
Due after one year through five years	1,978
Due after five years through 10 years	2,349
Due after 10 years	3,891
Estimated fair value	10,485		9,711
Fixed maturity securities held under trust for the benefit of reinsured companies	427		377
Eligible securities deposited for the benefit of policyholders	19		19
Fair market value of company's pledged securities	434		677
RMBS
Amortized Cost
Amortized cost	1,406
Estimated Fair Value
Estimated fair value	1,416
CMBS
Amortized Cost
Amortized cost	689
Estimated Fair Value
Estimated fair value	703
Fixed maturity securities
Amortized Cost
Amortized cost	10,019	[1]	9,488	[1]
Estimated Fair Value
Estimated fair value	$ 10,485

[1] Ratings in the tables above represent the lower of the Moody’s and S&P classifications except for bonds purchased for loss mitigation or risk management strategies, which use internal ratings classifications. The Company’s portfolio consists primarily of high-quality, liquid instruments.