SUBSEQUENT EVENTS (DETAILS) (USD $)	12 Months Ended				3 Months Ended		12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Sep. 30, 2012 Aircraft Agreement [Member] aircraft	Jun. 30, 2012 Aircraft Agreement [Member] aircraft	Dec. 31, 2011 Scenario, Actual [Member] Stock Split [Member]		Dec. 31, 2011 Scenario, Adjustment [Member] Stock Split [Member]	Dec. 31, 2011 Scenario, Plan [Member] Stock Split [Member]		Dec. 31, 2010 Scenario, Plan [Member] Stock Split [Member]
Subsequent Event [Line Items]
Common stock, shares outstanding							35,500,000			71,000,000
Preferred stock	$ 0	$ 0					$ 0			$ 0
Common stock	37,900,000	37,000,000					37,900,000	[1],[2]		37,900,000	[1],[2]
Capital in excess of par value	840,000,000	815,500,000					840,000,000			840,000,000
Treasury stock (common)	(125,300,000)	(46,000,000)					(125,300,000)	[3]		(125,300,000)	[3]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(390,000,000)	(267,200,000)					(390,000,000)			(390,000,000)
Retained earnings	810,600,000	566,100,000					810,600,000			810,600,000
Stockholders' Equity Attributable to Parent	1,173,200,000	1,105,400,000	872,100,000	661,900,000			1,173,200,000			1,173,200,000
Common stock, par value	$ 1	$ 1								$ 0.50
Common stock, shares issued	37,866,522	37,010,140								75,733,040		74,020,280
Treasury stock, shares	2,391,747	1,086,172								4,783,494		2,172,344
Net Income	244,500,000	251,100,000	121,600,000				244,500,000		0.00	244,500,000
Basic Earnings Per Share:	$ 6.81	$ 7.01	$ 3.39				$ 6.81		$ (3.40)	$ 3.41
Diluted Earnings Per Share:	$ 6.66	$ 6.83	$ 3.36				$ 6.66		$ (3.33)	$ 3.33
Basic	35,878,000	35,822,000	35,815,000				35,878,000		35,878,000	71,756,000
Diluted	36,710,000	36,786,000	36,154,000				36,710,000		36,710,000	73,420,000
Authorized amount under share repurchase program	$ 50,000,000
Number of Aircraft Delivered						2
Number Of Aircraft Sold					2

[1] Shares issued increase as follows: 2011 - 75,733,044; 2010 - 74,020,280

[2] Par is reduced to $0.50

[3] Treasury shares increase as follows: 2011 - 4,783,494; 2010 - 2,172,344