Income Taxes (Reconciliation between the Company's federal income tax (expense) benefit at statutory rates and the recorded income tax (expense) benefit) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income tax expense at statutory rates	$ (423)	$ (447)	$ (301)
Tax benefit from tax exempt income	119	97	84
Foreign taxes and credits	(6)	(1)	(13)
Other tax expense	(9)	(10)	(9)
Income tax (expense) benefit	$ (319)	$ (361)	$ (239)