Shareholders' Equity Shareholder's Equity (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2010
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments	$ 4,300,000,000
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	3,200,000,000	4,900,000,000
Cash and Cash Equivalents, at Carrying Value	7,276,000,000	8,406,000,000	9,429,000,000			9,123,000,000
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	14,800,000,000
Statutory Accounting Practices, Statutory Capital and Surplus Required	5,500,000,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	110
Stock Repurchased During Period, Shares	48
Treasury Stock Acquired, Average Cost Per Share	$ 65.52
Common stock repurchases	(3,170,000,000)	(3,084,000,000)	(2,994,000,000)
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	83
Cash Dividend Annual Rate Per Share				$ 1.12	$ 0.85
Extraordinary Dividends [Member]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	430,000,000	1,200,000,000
Unregulated Operation [Member]
Cash and Cash Equivalents, at Carrying Value	$ 1,000,000,000