Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule Of Share Based Compensation Stock Options Activity Table Text Block

					Weighted-
			Weighted-		Average
			Average		Remaining	Aggregate
			Exercise		Contractual	Intrinsic
		Shares	Price		Term	Value
Outstanding at January 1, 2013		3,360,072	$	67.16
Granted		49,972		83.11
Exercised		(107,835)		55.85
Cancelled or expired		(53,510)		83.80
Outstanding at December 31, 2013		3,248,699	$	67.51	5.2	$	76,089,000
Options vested and expected to vest at
	December 31, 2013	3,245,409	$	67.50	5.2	$	76,022,000
Options exercisable at December 31, 2013		2,478,838	$	67.12	4.8	$	60,013,000

Schedule Of Share Based Payment Award Stock Options Valuation Assumptions Table Text Block

	December 31,
	2013	2012	2011
Expected volatility	36.00%	36.00%	35.00%
Expected life	5.0 years	5.0 years	7.1 years
Risk free interest rate	0.91%	1.05%	2.90%
Expected dividend yield	4.30%	4.30%	4.40%

Schedule Of Sharebased Compensation Restricted Stock And Restricted Stock Units Activity Table Text Block

			Weighted-Average
			Grant-Date
Unvested Shares		Shares	Fair Value
	Unvested at January 1, 2013	48,020	$	78.61
	Granted	10,318		83.11
	Vested	(16,018)		74.51
	Cancelled or expired	(12,656)		86.00
	Unvested at December 31, 2013	29,664		79.23

Schedule Of Sharebased Compensation Restricted Operating Partnership Units Activity Table [Text Block]

			Weighted-Average
			Grant-Date
Unvested Units		Units	Fair Value
	Unvested at January 1, 2013	640,670	$	69.61
	Granted	400,500		79.77
	Vested	(252,052)		65.08
	Cancelled or expired	(23,147)		74.31
	Unvested at December 31, 2013	765,971		76.27