Share-Based Compensation and Employee Ownership Plans Narrative (Details) (Equity Plans, USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended								6 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Employee Stock Option	Jun. 30, 2014 Employee Stock Option Minimum	Jun. 30, 2014 Employee Stock Option Maximum	Jun. 30, 2014 Restricted Shares and Restricted Stock Units (RSUs)		Dec. 31, 2013 Restricted Shares and Restricted Stock Units (RSUs)	Jun. 30, 2014 Stock Appreciation Rights (SARs)	Dec. 31, 2013 Stock Appreciation Rights (SARs)	Jun. 30, 2014 Restricted Stock Minimum	Jun. 30, 2014 Restricted Stock Maximum	Jun. 30, 2014 Restricted Stock Units (RSUs) Non-employee Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense								$ 46.9			$ 0.2	$ 0.3
Shares authorized under compensation plan, in shares	17,725,000		17,725,000
Stock compensation award, vesting period						2 years	5 years						2 years	5 years
Stock options, initial term					7 years
SAR's, initial term											5 years
Shares available for issuance under compensation plan, in shares	1,700,000		1,700,000
Stock-compensation expense recognized in connection with compensation plan	5.7	4.7	10.5	9.5
Tax benefit of stock-compensation expense recognized in connection with compensation plan	$ 1.9	$ 3.7	$ 2.9	$ 5.7
Vested, shares								3,861,512			0				216,834
Granted, shares															158,791
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number								17,236,617	[1]	13,551,544	400,000	400,000			424,479

[1] Included in the outstanding balance are 1,925,750 performance linked restricted stock units awarded to employees of the Company in December 2013 and January 2014. The awards will vest on June 10, 2019 and will be earned only to the extent that the Company attains specified performance goals relating to its volume-weighted average share price and the aggregate net income for the years from 2014 to 2018. The actual number of RSUs ultimately earned could vary from zero, if performance goals are not met, to as much as 100% of the targeted award. Each RSU is equal to the one share of the Company’s Class A common stock. Compensation expense is recognized to the extent that it is probable that the Company will attain the performance goals.