Significant Financing Transactions (Schedule of Equity Units) (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended
	Jun. 07, 2013 Class A	Jun. 07, 2013 Class B	Jun. 30, 2013 Remarketable Subordinated Notes [Member] Class A	Jun. 07, 2013 Remarketable Subordinated Notes [Member] Class A	Jun. 30, 2013 Remarketable Subordinated Notes [Member] Class B	Jun. 07, 2013 Remarketable Subordinated Notes [Member] Class B
Capital Unit [Line Items]
Units Issued	11	11
Total Net Proceeds	$ 533.5	$ 533.5
Total Long-term Debt				550.0		550.0
RSN Annual Interest Rate			1.07%		1.18%
Stock Purchase Contract Annual Rate	5.055%	4.82%
Stock Purchase Contract Liability	$ 76.7	$ 79.3