Investments - Commerical Mortgage Loans by Property Type and Geographic Region (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	$ 2,252	$ 2,851
Commercial mortgage loans maturing in 2014	177
Commercial mortgage loans maturing in 2015	287
Commercial mortgage loans maturing in 2016	719
Commercial mortgage loans maturing in 2017	252
Commercial mortgage loans maturing after 2017	817
Commercial Mortgage Loans Commitments To Extend Credit	7
Pacific Region [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	805	966
South Atlantic Region [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	564	730
New England Region [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	379	387
Central Region [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	260	352
Middle Atlantic [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	201	300
Mountain [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	43	116
Office Buildings [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	761	866
Apartment Buildings [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	321	571
Industrial [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	450	532
Hotels [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	407	463
Retail Facilities [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	285	346
Other Property [Member]
Mortgage Loans on Real Estate [Line Items]
Commercial Mortgage Loans	$ 28	$ 73