Investments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Increase (decrease) in gross AFS securities unrealized losses	$ (959)
Number of partnerships in alternative investment portfolio	137	121
Investment commitments	1,300
Investment commitments for limited partnerships	573
Investment commitments for private placements	308
Investment commitments for mortgage loans on real estate	448
California and Texas [Member]
Largest mortgage loan concentration in geographic region	32.00%	32.00%
Federal Home Loan Mortgage Corporation
Fair value	2,500	2,600
Concentration risk, percentage	3.00%	3.00%
Fannie Mae
Fair value	1,600	1,700
Concentration risk, percentage	2.00%	2.00%
Electric Industry [Member]
Fair value	9,700	8,700
Concentration risk, percentage	10.00%	9.00%
Banking Industry [Member]
Fair value	5,000	5,000
Concentration risk, percentage	5.00%	5.00%
Corporate Bonds [Member]
Percentage of fair value rated as investment grade	96.00%	96.00%
Amortized cost of portfolio rated below investment grade	3,200	3,000
Fair value of portfolio rated below investment grade	3,300	2,900
CDOs [Member]
Percentage of fair value rated as investment grade	95.00%	94.00%
Amortized cost of portfolio rated below investment grade	15	16
Fair value of portfolio rated below investment grade	$ 13	$ 13
MBS [Member]
Projected default rate on existing delinquencies on MBS (low end of range)	10.00%
Projected default rate on existing delinquencies on MBS (high end of range)	100.00%
Severity of second lien loans	100.00%
Severity of first lien loans	30.00%