Stockholders' Equity (Share Repurchase Program) (Narrative) (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended			5 Months Ended		132 Months Ended	1 Months Ended	6 Months Ended	33 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014	Dec. 31, 2014	Jun. 30, 2012	Feb. 28, 2013	Jun. 30, 2013	Dec. 31, 2013	Jan. 31, 2014	Jun. 30, 2001	Apr. 30, 2011
Equity, Class of Treasury Stock [Line Items]
Payments for Repurchase of Common Stock	$ 2,000	$ 1,000	$ 400
Repurchased and retired, shares	30,110	20,400	7,778
January 2014 Buyback Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Share buyback plan, authorized amount										5,000
Payments for Repurchase of Common Stock				1,000
Repurchased and retired, shares				15,100
August 2014 Buyback Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Payments for Repurchase of Common Stock					700
Repurchased and retired, shares					10,400
June 2001 Buyback Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Share buyback plan, authorized amount											2,000
Repurchased and retired, shares						42,000
Open Market Purchases [Member]
Equity, Class of Treasury Stock [Line Items]
Payments for Repurchase of Common Stock	300
Repurchased and retired, shares	4,700
December 2012 Buyback Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Share buyback plan, authorized amount			1,000
Payments for Repurchase of Common Stock							1,000
Repurchased and retired, shares								20,400
April 2011 Buyback Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Share buyback plan, authorized amount												2,000
Payments for Repurchase of Common Stock									$ 284
Repurchased and retired, shares									5,500