Quarterly Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 1,977,947	$ 2,009,575	$ 1,962,636	$ 1,802,570	$ 1,785,922	$ 1,850,653	$ 1,836,981	$ 1,681,540	$ 7,752,728	$ 7,155,096	$ 6,626,648
Gross profit	723,868	774,422	768,100	707,859	679,709	724,041	720,994	653,847	2,974,249	2,778,591	2,579,989
Earnings from continuing operations	171,835	225,683	210,581	170,041	172,227	217,045	247,988	160,267	778,140	797,527	650,075
Earnings from continuing operations (in dollars per basic share)	$ 1.04	$ 1.36	$ 1.26	$ 1.00	$ 1.01	$ 1.27	$ 1.45	$ 0.92	$ 4.67	$ 4.66	$ 3.58
Earnings from continuing operations (in dollars per diluted share)	$ 1.03	$ 1.34	$ 1.25	$ 0.99	$ 1.00	$ 1.26	$ 1.43	$ 0.91	$ 4.61	$ 4.60	$ 3.53
Net earnings	$ 169,294	$ 231,844	$ 213,959	$ 160,138	$ 193,963	$ 269,114	$ 330,049	$ 210,003	$ 775,235	$ 1,003,129	$ 811,070
Net earnings (in dollars per basic share)	$ 1.03	$ 1.40	$ 1.29	$ 0.94	$ 1.14	$ 1.58	$ 1.93	$ 1.21	$ 4.65	$ 5.86	$ 4.47
Net earnings (in dollars per diluted share)	$ 1.02	$ 1.38	$ 1.27	$ 0.93	$ 1.13	$ 1.56	$ 1.91	$ 1.20	$ 4.59	$ 5.78	$ 4.41