Fair Value (Fair Value Option Gains (Losses) for Residential Mortgage Loans) (Details) (Residential Mortgage Loans - FVO [Member], Net Investment Income [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Residential Mortgage Loans - FVO [Member] | Net Investment Income [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Instrument-specific credit risk based on changes in credit spreads for non-agency loans and adjustments in individual loan quality	$ 2	$ 0
Other changes in estimated fair value	1	0
Total gains (losses) recognized in net investment income	$ 3	$ 0