Shareholders Equity (Details 2) - USD ($) shares in Thousands, $ in Millions		6 Months Ended
		Jun. 30, 2015		Jun. 30, 2014
Treasury Stock [Roll Forward]
Treasury Stock, Shares, Beginning (shares)	[1]	7,609
Treasury Stock, Shares, Ending (shares)		27,828
Treasury Stock, Value, Beginning	[1]	$ 105
Purchases		611		$ 479
Cancellation of treasury stock		0		0
Treasury Stock, Value, Ending		$ 316
Treasury Stock
Treasury Stock [Roll Forward]
Treasury Stock, Shares, Beginning (shares)		7,609
Purchases (in shares)	[2]	50,081
Cancellations (in shares)		(29,862)
Treasury Stock, Shares, Ending (shares)		27,828
Treasury Stock, Value, Beginning		$ 105
Purchases		611	[2]	479
Cancellation of treasury stock		(400)		$ (583)
Treasury Stock, Value, Ending		$ 316

[1] Certain prior year amounts have been revised - Refer to Note 1 - Basis of Presentation for additional information.

[2] Includes associated fees.