Fair Value Measurement and Fair Value of Financial Instruments (Details 4) (USD $) In Millions, unless otherwise specified					6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Other debt securities, Direct bank purchase bonds	Dec. 31, 2013 Other debt securities, Direct bank purchase bonds	Jun. 30, 2014 Other debt securities, Direct bank purchase bonds Minimum Return on equity	Jun. 30, 2014 Other debt securities, Direct bank purchase bonds Maximum Return on equity	Jun. 30, 2014 Other debt securities, Direct bank purchase bonds Weighted Average Return on equity	Jun. 30, 2014 Level 3 Other debt securities, Direct bank purchase bonds
Significant unobservable inputs, Level 3 assets
Market-required return on capital (as a percent)					8.00%	10.00%	9.90%
Probability of default (as a percent)					0.00%	8.00%	0.50%
Loss severity (as a percent)					10.00%	60.00%	31.60%
Securities available for sale	$ 14,670	$ 15,817	$ 1,897	$ 1,960				$ 1,897