Employee Incentive Plans Employee Incentive Plans, Weighted Average Grant Date Fair Value (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted-Average Grant-Date Fair Value per Share	$ 72.09	$ 66.42	$ 58.65
Restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted-Average Grant-Date Fair Value per Share	69.83	67.42	57.70
EVA-Based Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted-Average Grant-Date Fair Value per Share	0.00	0.00	57.75
TSR-Based Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted-Average Grant-Date Fair Value per Share	$ 95.68	$ 83.18	$ 0.00