Investments (Related Party Investment Transactions) (Details) (Affiliated Entity [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Affiliated Entity [Member]
Invested Assets Transferred To And From Affiliates
Estimated fair value of invested assets transferred to affiliates		$ 97	$ 781	$ 4
Amortized cost of invested assets transferred to affiliates		89	688	4
Net investment gains (losses) recognized on transfers		8	93	0
Estimated fair value of invested assets transferred from affiliates	$ 437	$ 882	$ 882	$ 0