Earnings per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Reconciliation of information used in computing basic and diluted earnings per share [Abstract]
Earnings from continuing operations	$ 212,902	$ 239,198	$ 409,729	$ 413,989
(Loss) earnings from discontinued operations, net	1,199	10,571	435	30,685
Net earnings	$ 214,101	$ 249,769	$ 410,164	$ 444,674
Basic earnings (loss) per common share:
Earnings from continuing operations (in dollars per basic share)	$ 1.16	$ 1.28	$ 2.23	$ 2.22
Earnings (loss) from discontinued operations, net (in dollars per basic share)	$ 0.01	$ 0.06	$ 0.00	$ 0.16
Net earnings (in dollars per basic share)	$ 1.17	$ 1.34	$ 2.23	$ 2.38
Weighted average shares outstanding - basic (in shares)	183,494,000	186,443,000	183,625,000	186,522,000
Diluted earnings (loss) per common share:
Earnings from continuing operations (in dollars per diluted share)	$ 1.15	$ 1.26	$ 2.20	$ 2.18
Earnings (loss) from discontinued operations, net (in dollars per diluted share)	$ 0.01	$ 0.06	$ 0.00	$ 0.16
Net earnings (in dollars per diluted share)	$ 1.15	$ 1.32	$ 2.20	$ 2.34
Weighted average shares outstanding - diluted (in shares)	185,780,000	189,705,000	186,171,000	189,905,000
Reconciliation Of Share Amounts Used In Computing Earnings Per Share [Abstract]
Weighted average shares outstanding - basic (in shares)	183,494,000	186,443,000	183,625,000	186,522,000
Dilutive effect of assumed exercise of employee stock options, SAR's and performance shares (in shares)	2,286,000	3,262,000	2,546,000	3,383,000
Weighted average shares outstanding - diluted (in shares)	185,780,000	189,705,000	186,171,000	189,905,000
Weighted average number of anti-dilutive potential common shares excluded from reconciliation calculations (in shares)	3,135,000	1,513,000	2,784,000	1,184,000