Compensation Plans (Details 2) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended													1 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Stock Options	Dec. 31, 2011 Stock Options	Dec. 31, 2010 Stock Options	Dec. 31, 2012 Restricted Stock and Performance Restricted Stock Units	Dec. 31, 2011 Restricted Stock and Performance Restricted Stock Units	Dec. 31, 2010 Restricted Stock and Performance Restricted Stock Units	Dec. 31, 2012 Restricted Stock and Performance Restricted Stock Units Minimum	Dec. 31, 2012 Restricted Stock and Performance Restricted Stock Units Maximum	Dec. 31, 2012 Restricted stock	Dec. 31, 2012 Restricted Stock Units	Aug. 31, 2006 Restricted Stock Units Chairman and Chief Executive Officer	Dec. 31, 2012 Restricted Stock Units Chairman and Chief Executive Officer	Dec. 31, 2012 23.34 - 25.52 Stock Options	Dec. 31, 2012 27.11 - 28.35 Stock Options	Dec. 31, 2012 31.95 - 41.64 Stock Options
Shares Authorized under Stock Option Plan Exercise Price Range
Exercise Price Range, Lower Range Limit (in dollars per share)																$ 23.34	$ 27.11	$ 31.95
Exercise Price Range, Upper Range Limit (in dollars per share)																$ 25.52	$ 28.35	$ 41.64
Shares under Options (in shares)				3,127,000												910,000	739,000	1,478,000
Weighted Average Exercise Price (in dollars per share)				$ 31.16												$ 23.34	$ 28.28	$ 37.41
Weighted Average Remaining Contractual Term				6 years 10 months 24 days												6 years 1 month 6 days	6 years 9 months 18 days	7 years 4 months 24 days
Currently Exercisable - Shares Under Options (in shares)				539,000												54,000	210,000	275,000
Currently Exercisable - Weighted Average Exercise Price (in dollars per share)				$ 32.09												$ 23.34	$ 28.12	$ 36.84
Share-based Compensation Arrangement by Share-based Payment Award, Options Unvested
Unvested at the beginning of the period (in shares)				3,285,000
Granted (in shares)				455,000
Vested (in shares)				(1,138,000)
Forfeited (in shares)				(14,000)
Unvested at the end of the period (in shares)				2,588,000	3,285,000
Unvested at the beginning of the period, weighted average grant date fair value (in dollars per share)				$ 3.77
Granted, weighted average grant date fair value (in dollars per share)				$ 6.34	$ 5.97	$ 5.17
Vested, weighted average grant date fair value (in dollars per share)				$ 3.59
Forfeited, weighted average grant date fair value (in dollars per share)				$ 3.67
Unvested at the end of the period, weighted average grant date fair value (in dollars per share)				$ 4.30	$ 3.77
Share-based Compensation Arrangement by Share-based Payment Award, Options, Other Information
Total vesting date intrinsic values (at vesting) of shares under options vested				$ 18.0	$ 15.8	$ 10.7
Total intrinsic value of vested shares under options at the end of the period				7.0
Proceeds received from options exercised				51.6	30.8	6.3
Total intrinsic value (at exercise) of options exercised				51.0	13.4	2.3
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology
Implied volatility traded option on common stock period				30 days
Risk-free rate (as a percent)				1.09%	2.58%	2.77%
Expected life				5 years 10 months 24 days	6 years 6 months	6 years 3 months 18 days
Expected volatility (as a percent)				32.70%	31.80%	35.00%
Expected dividend yield (as a percent)				5.90%	6.10%	6.20%
Restricted Stock and Performance Restricted Stock Units
Stock-based awards, vesting period										3 years	5 years				10 years
Performance restricted stock unit is convertible into common stock (in shares)							1.00
Shares withheld to offset tax withholding obligations (in shares)							361,000	136,000	154,000
Weighted-average remaining vesting period of restricted stock and restricted stock units							3 years
Total fair values (at vesting) of restricted stock and restricted stock units vested							38.6	14.4	12.5
Unvested restricted stock and performance restricted stock units activity
Unvested at the beginning of the period (in shares)												339,000	1,478,000
Granted (in shares)													456,000	219,000
Vested (in shares)												(186,000)	(707,000)
Forfeited (in shares)												(8,000)	(7,000)
Unvested at the end of the period (in shares)												145,000	1,220,000		317,000
Unvested at the beginning of the period, Weighted Average Grant Date Fair Value (in dollars per share)												$ 27.75	$ 32.59
Granted, Weighted Average Grant Date Fair Value (in dollars per share)													$ 41.67
Vested, Weighted Average Grant Date Fair Value (in dollars per share)												$ 27.55	$ 33.03
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share)												$ 26.72	$ 38.29
Unvested at the end of the period, Weighted Average Grant Date Fair Value (in dollars per share)												$ 27.24	$ 35.16
Employee Benefit Plan
Matching contribution by Company, maximum percentage of participant's eligible compensation	4.00%
Matching contributions to Employee Benefit Plan	$ 0.8	$ 0.8	$ 0.9