Stock-Based Compensation Programs (Details)	1 Months Ended			12 Months Ended
	Jan. 31, 2015 $ / shares shares	Jan. 31, 2014 shares	Jan. 31, 2013 shares	Dec. 31, 2015 USD ($) installment $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares
Restricted stock activity, Weighted average grant price
Share based compensation expense | $				$ 24,700,000	$ 25,100,000	$ 24,500,000
Expenses for share-based compensation arrangements, after tax | $				15,400,000	$ 15,600,000	14,900,000
Unrecognized compensation cost related to nonvested share-based compensation arrangements | $				$ 35,000,000
Expected weighted-average period for recognition of unrecognized stock-based compensation costs				2 years 6 months
Stock option and SSARs
Stock-Based Compensation Programs
Number of equal installments commencing one year from the date of grant | installment				4
Vesting period				1 year
Expiration period of options				10 years
Outstanding Options, Number of Shares
Beginning of year (in shares)	9,738,030			9,738,030
Granted (in shares)				1,231,865
Exercised (in shares)				(1,201,987)
Canceled/forfeited (in shares)				(51,657)
End of the period (in shares)				9,716,251	9,738,030
Vested and exercisable, end of period (in shares)				6,748,255
Reserved for future grants (in shares)				8,657,680
Outstanding Options, Weighted Average Exercise Price
Beginning of year (in dollars per share) | $ / shares	$ 32.76			$ 32.76
Granted (in dollars per share) | $ / shares				66.15
Exercised (in dollars per share) | $ / shares				27.92
Canceled/forfeited (in dollars per share) | $ / shares				46.74
End of period (in dollars per share) | $ / shares				37.50	$ 32.76
Vested and exercisable, end of period (in dollars per share) | $ / shares				$ 30.15
Weighted average remaining contractual term of options outstanding				5 years 3 months 18 days
Aggregate intrinsic value of options outstanding | $				$ 342,300,000
Weighted average remaining contractual term of options vested and exercisable				4 years 1 month 6 days
Aggregate intrinsic value of options vested and exercisable | $				$ 287,400,000
Total fair value of options vested | $				$ 11,700,000	$ 13,300,000	$ 11,400,000
Weighted average fair value at grant date (in dollars per share) | $ / shares				$ 14.20	$ 9.81	$ 8.69
Weighted average assumptions used in estimation of fair values of options
Expected dividend yield (as a percent)				0.79%	1.06%	1.13%
Expected stock price volatility (as a percent)				22.11%	21.41%	22.02%
Risk-free interest rate (as a percent)				1.39%	1.65%	1.02%
Expected life of options				5 years 10 months 6 days	5 years 6 months	5 years 6 months
Stock options
Outstanding Options, Weighted Average Exercise Price
Cash received from options exercised | $				$ 21,600,000	$ 22,900,000	$ 17,000,000
Intrinsic value of options exercised | $				32,900,000	31,400,000	17,100,000
Tax benefit from exercise of options | $				$ 21,300,000
Restricted stock activity, Weighted average grant price
Maximum employer's contribution as a percentage of each participating employee's monthly payroll deduction				20.00%
Maximum employer's contribution to each participating employee | $				$ 500
Company contributions | $				$ 3,500,000	$ 3,500,000	3,500,000
Restricted shares and restricted stock units
Stock-Based Compensation Programs
Vesting period				5 years
Restricted stock activity, Number of shares
Beginning of the period (in shares)	1,220,661			1,220,661
Granted (in shares)				192,831
Vested (in shares)				(546,294)
Canceled/forfeited (in shares)				(5,253)
End of the period (in shares)				861,945	1,220,661
Restricted stock activity, Weighted average grant price
Beginning of the period (in dollars per share) | $ / shares	$ 33.92			$ 33.92
Granted (in dollars per share) | $ / shares				68.83
Vested (in dollars per share) | $ / shares				28.17
Canceled/forfeited (in dollars per share) | $ / shares				52.62
End of the period (in dollars per share) | $ / shares				$ 45.27	$ 33.92
PCEQs
Restricted stock activity, Number of shares
Granted (in shares)	116,559	143,305	148,875
Restricted stock activity, Weighted average grant price
Share based compensation expense | $				$ 7,100,000	$ 6,900,000	$ 7,600,000
PCEQs | Minimum
Restricted stock activity, Weighted average grant price
Vest range of participant's assigned award opportunity (as a percent)		0.00%
PCEQs | Maximum
Restricted stock activity, Weighted average grant price
Vest range of participant's assigned award opportunity (as a percent)		200.00%