Earnings per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Reconciliation of information used in computing basic and diluted earnings per share [Abstract]
Earnings from continuing operations	$ 217,443	$ 258,058	$ 393,767	$ 425,271
Earnings (loss) from discontinued operations, net	(3,484)	71,991	(19,670)	114,781
Net earnings	$ 213,959	$ 330,049	$ 374,097	$ 540,052
Basic earnings (loss) per common share:
Earnings from continuing operations (in dollars per basic share)	$ 1.31	$ 1.51	$ 2.34	$ 2.47
Earnings (loss) from discontinued operations, net (in dollars per basic share)	$ (0.02)	$ 0.42	$ (0.12)	$ 0.67
Net earnings (in dollars per basic share)	$ 1.29	$ 1.93	$ 2.23	$ 3.13
Weighted average shares outstanding - basic (in shares)	166,474,000	171,111,000	168,103,000	172,273,000
Diluted earnings (loss) per common share:
Earnings from continuing operations (in dollars per diluted share)	$ 1.29	$ 1.49	$ 2.31	$ 2.44
Earnings (loss) from discontinued operations, net (in dollars per diluted share)	$ (0.02)	$ 0.42	$ (0.12)	$ 0.66
Net earnings (in dollars per diluted share)	$ 1.27	$ 1.91	$ 2.19	$ 3.10
Weighted average shares outstanding - diluted (in shares)	168,857,000	173,097,000	170,450,000	174,325,000
Reconciliation Of Share Amounts Used In Computing Earnings Per Share [Abstract]
Weighted average shares outstanding - basic (in shares)	166,474,000	171,111,000	168,103,000	172,273,000
Dilutive effect of assumed exercise of employee stock options, SAR's and performance shares (in shares)	2,383,000	1,986,000	2,347,000	2,052,000
Weighted average shares outstanding - diluted (in shares)	168,857,000	173,097,000	170,450,000	174,325,000
Weighted average number of anti-dilutive potential common shares excluded from reconciliation calculations (in shares)	48,000	61,000	0	15,000