Earnings Per Share ("EPS") (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			213 Months Ended
	Dec. 31, 2013 agreement	Dec. 31, 2012 agreement	Dec. 31, 2011 agreement	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dividend equivalent units outstanding	0.2			0.2
Number Of Accelerated Share Repurchase Agreements Executed	4	4	2
Number of ASRs executed	4	4	2
Shares repurchased during period, shares	2.7	8.1	7.9	110.3
Treasury shares purchased (in value)	$ 82.0	$ 190.0	$ 250.0	$ 4,680.0
Class A Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	2.4	3.8	5.7
Maximum [Member] | Contingently Issuable Shares Excluded From Computation Of Diluted EPS [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Additional shares to be included in diluted EPS calculation if related performance conditions are satisfied	0.1			0.1
Minimum [Member] | Contingently Issuable Shares Excluded From Computation Of Diluted EPS [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Additional shares to be included in diluted EPS calculation if related performance conditions are satisfied	0.5			0.5