Stock Option And Grant Plan (Summary Of Stock Options) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of year, Options	7,122	7,545	7,319
Granted, Options	103	1,109	1,104
Issued pursuant to apache Acquisition, Options	0	0	418
Exercised, Options	(993)	(1,464)	(1,179)
Forfeited, Options	(66)	(68)	(117)
Outstanding, end of year, Options	6,166	7,122	7,545
Vested and Exercisable, end of year, Options	4,351	4,094	4,251
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning of period, Weighted Average Exercise Price	$ 42.85	$ 35.10	$ 29.92
Granted, Weighted Average Exercise Price	$ 81.87	$ 67.53	$ 58.50
Issued pursuant to Apache acquisition	$ 0.00	$ 0.00	$ 18.66
Exercised, Weighted Average Exercise Price	$ 34.26	$ 21.85	$ 19.33
Forfeited, Weighted Average Exercise Price	$ 53.75	$ 36.90	$ 33.27
Outstanding, end of period, Weighted Average Exercise Price	$ 44.77	$ 42.85	$ 35.10
Vested and Exercisable, end of period, Weighted Average Exercise Price	$ 38.18	$ 33.91	$ 27.98
Outstanding, Weighted Average Remaining Contractual Term (in years)	5 years 11 months 26 days	6 years 9 months 11 days	6 years 7 months 28 days
Vested and Exercisable, Weighted Average Remaining Contractual Term (in years)	5 years 1 month 17 days	5 years 5 months 23 days	5 years 2 months 12 days
Outstanding, Aggregate Intrinsic Value	$ 261,601	$ 174,383	$ 168,837
Vested and Exercisable, Aggregate Intrinsic Value	$ 213,304	$ 136,851	$ 124,550