Shareholders' Equity (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2011
Shareholders' Equity Disclosure [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	$ 4,600,000,000	$ 3,200,000,000
Cash and cash equivalents	7,495,000,000	7,276,000,000	8,406,000,000			9,429,000,000
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	14,700,000,000
Statutory Accounting Practices, Statutory Capital and Surplus Required	7,100,000,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	100
Stock Repurchased and Retired During Period, Shares	49
Treasury Stock Acquired, Average Cost Per Share	$ 82.57
Payments for Repurchase of Common Stock	4,008,000,000	3,170,000,000	3,084,000,000
Cash Dividend Annual Rate Per Share				$ 1.50	$ 1.12
Parent [Member]
Shareholders' Equity Disclosure [Line Items]
Cash and cash equivalents	738,000,000
Extraordinary Dividends [Member]
Shareholders' Equity Disclosure [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	$ 1,500,000,000	$ 430,000,000