Investments and Derivative Instruments (Details 10) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Variable Interest Entities Primary Beneficiary
Total Assets	$ 187	$ 199
Total Liabilities	14	33
Maximum Exposure to Loss	182	177
Collateralized Debt Obligations [Member]
Variable Interest Entities Primary Beneficiary
Total Assets	0	31
Collateralized Debt Obligations [Member] | Consolidated VIEs [Member]
Variable Interest Entities Primary Beneficiary
Total Assets	14	31
Total Liabilities	14	33
Maximum Exposure to Loss	0	0
Investment Fund [Member] | Consolidated VIEs [Member]
Variable Interest Entities Primary Beneficiary
Total Assets	170	164
Total Liabilities	0	0
Maximum Exposure to Loss	179	173
Limited partnerships [Member]
Variable Interest Entities Primary Beneficiary
Variable Interest Entity Assets Included in Limited Partnerships and Other Alternative Investments	3	4
Limited partnerships [Member] | Consolidated VIEs [Member]
Variable Interest Entities Primary Beneficiary
Total Liabilities	0	0
Maximum Exposure to Loss	$ 3	$ 4