Earnings per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of information used in computing basic and diluted earnings per share [Abstract]
Earnings from continuing operations	$ 210,812	$ 263,652	$ 294,352	$ 196,989	$ 208,224	$ 233,330	$ 205,156	$ 186,409	$ 965,805	$ 833,119	$ 773,186
(Loss) earnings from discontinued operations, net									37,324	(22,049)	122,057
Net earnings	$ 193,963	$ 269,114	$ 330,049	$ 210,003	$ 159,860	$ 241,046	$ 214,101	$ 196,063	$ 1,003,129	$ 811,070	$ 895,243
Basic earnings (loss) per common share:
Earnings from continuing operations (in dollars per basic share)	$ 1.24	$ 1.55	$ 1.72	$ 1.14	$ 1.17	$ 1.28	$ 1.12	$ 1.01	$ 5.64	$ 4.59	$ 4.16
Earnings (loss) from discontinued operations, net (in dollars per basic share)									$ 0.22	$ (0.12)	$ 0.66
Net earnings (in dollars per basic share)	$ 1.14	$ 1.58	$ 1.93	$ 1.21	$ 0.90	$ 1.33	$ 1.17	$ 1.07	$ 5.86	$ 4.47	$ 4.82
Weighted average shares outstanding - basic (in shares)									171,271,000	181,551,000	185,882,000
Diluted earnings (loss) per common share:
Earnings from continuing operations (in dollars per diluted share)	$ 1.22	$ 1.53	$ 1.70	$ 1.12	$ 1.16	$ 1.27	$ 1.10	$ 1.00	$ 5.57	$ 4.53	$ 4.09
Earnings (loss) from discontinued operations, net (in dollars per diluted share)									$ 0.22	$ (0.12)	$ 0.65
Net earnings (in dollars per diluted share)	$ 1.13	$ 1.56	$ 1.91	$ 1.20	$ 0.89	$ 1.31	$ 1.15	$ 1.05	$ 5.78	$ 4.41	$ 4.74
Weighted average shares outstanding - diluted (in shares)									173,547,000	183,993,000	188,887,000
Reconciliation Of Share Amounts Used In Computing Earnings Per Share [Abstract]
Weighted average shares outstanding - basic (in shares)									171,271,000	181,551,000	185,882,000
Dilutive effect of assumed exercise of employee stock options, SAR's and performance shares (in shares)									2,276,000	2,442,000	3,005,000
Weighted average shares outstanding - diluted (in shares)									173,547,000	183,993,000	188,887,000
Weighted average number of anti-dilutive potential common shares excluded from reconciliation calculations (in shares)									0	2,950,000	1,333,000