Stockholders' Equity (Share Repurchase Program) (Narrative) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended				3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 January 2014 Buyback Plan [Member]	Jan. 31, 2014 January 2014 Buyback Plan [Member]	Sep. 30, 2014 August 2014 Buyback Plan [Member]	Sep. 30, 2014 August 2014 Buyback Plan [Member]	Sep. 30, 2014 Open Market Purchases [Member]	Sep. 30, 2014 Open Market Purchases [Member]	Sep. 30, 2013 December 2012 Buyback Plan [Member]	Dec. 31, 2012 December 2012 Buyback Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Share buyback plan, Authorized Amount				$ 5,000						$ 1,000
Repurchase of common stock			1,000				203	300
Prepayments / repurchase of common stock	$ 2,000	$ 1,000			$ 700				$ 1,000
Stock Repurchased and Retired During Period, Shares			15.1		8.6	8.6	3.1	4.7	20.4
Percentage of share repurchase agreement completed					80.00%	80.00%