Earnings per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reconciliation of information used in computing basic and diluted earnings per share [Abstract]
Earnings from continuing operations	$ 232,825	$ 226,235	$ 626,592	$ 651,506
Earnings (loss) from discontinued operations, net	(981)	42,879	(20,651)	157,660
Net earnings	$ 231,844	$ 269,114	$ 605,941	$ 809,166
Basic earnings (loss) per common share:
Earnings from continuing operations (in dollars per basic share)	$ 1.40	$ 1.33	$ 3.74	$ 3.79
Earnings (loss) from discontinued operations, net (in dollars per basic share)	$ (0.01)	$ 0.25	$ (0.12)	$ 0.92
Net earnings (in dollars per basic share)	$ 1.40	$ 1.58	$ 3.62	$ 4.71
Weighted average shares outstanding - basic (in shares)	166,021,000	170,544,000	167,401,000	171,690,000
Diluted earnings (loss) per common share:
Earnings from continuing operations (in dollars per diluted share)	$ 1.38	$ 1.31	$ 3.69	$ 3.75
Earnings (loss) from discontinued operations, net (in dollars per diluted share)	$ (0.01)	$ 0.25	$ (0.12)	$ 0.91
Net earnings (in dollars per diluted share)	$ 1.38	$ 1.56	$ 3.57	$ 4.65
Weighted average shares outstanding - diluted (in shares)	168,343,000	172,734,000	169,761,000	173,870,000
Reconciliation Of Share Amounts Used In Computing Earnings Per Share [Abstract]
Weighted average shares outstanding - basic (in shares)	166,021,000	170,544,000	167,401,000	171,690,000
Dilutive effect of assumed exercise of employee stock options, SAR's and performance shares (in shares)	2,322,000	2,190,000	2,360,000	2,180,000
Weighted average shares outstanding - diluted (in shares)	168,343,000	172,734,000	169,761,000	173,870,000
Weighted average number of anti-dilutive potential common shares excluded from reconciliation calculations (in shares)	54,130	0	10,441	0