Incentive Plans (Schedule Of Restricted Stock Award Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011
Restricted Stock Equity Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares/Units, Outstanding at beginning of year	2,559,779
Number of Shares granted	443,060
Forfeitures, number of shares	(63,105)
Awards vested	(1,082,122)
Number of Shares/Units, Outstanding at end of year	1,857,612
Weighted Average Grant-Date Fair Value, Outstanding at beginning of year	$ 28.85
Weighted Average Grant-Date Fair Value, Shares granted	$ 97.52
Weighted Average Grant-Date Fair Value, Shares forfeited	$ 54.51
Weighted Average Grant-Date Fair Value, Shares vested	$ 36.41
Weighted Average Grant-Date Fair Value, Outstanding at end of year	$ 39.95
Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares/Units, Outstanding at beginning of year	215,134
Number of Shares granted	202,411
Forfeitures, number of shares	(23,953)
Awards vested	(70,667)
Number of Shares/Units, Outstanding at end of year	322,925