Share Repurchase Program (Narrative) (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	0 Months Ended		1 Months Ended	3 Months Ended		9 Months Ended		22 Months Ended
	Aug. 10, 2012	Jun. 01, 2012	Nov. 08, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Nov. 08, 2012
Share Repurchase Program
Increase in authorized amount	$ 500,000,000	$ 500,000,000
Cumulative authorized amount	2,500,000,000
Authorization effective period	3 years	3 years
Remaining balance under share repurchase program						390,400,000
Common stock repurchased, shares			1,600	6,359	8,162	12,647	14,074	30,200
Common stock repurchased, average price per share			$ 83.68	$ 84.76	$ 61.51	$ 89.62	$ 59.69	$ 74.49
Common stock repurchased, value			$ 136,600,000	$ 538,972,000	$ 502,067,000	$ 1,133,328,000	$ 839,979,000	$ 2,200,000,000