Marketable Securities (Schedule Of Contractual Maturities Of Available-For-Sale Marketable Securities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Marketable Securities [Abstract]
Due in less than one year, Amortized Cost	$ 160.4	$ 185.4
Due in 1-5 years, Amortized Cost	621.1	498.3
Due after 5 years, Amortized Cost	18.4	21.5
Total available-for-sale marketable securities, Amortized Cost	799.9	705.2
Due in less than one year, Estimated Fair Value	160.6	185.8
Due in 1-5 years, Estimated Fair Value	622.2	500.9
Due after 5 years, Estimated Fair Value	17.9	20.5
Total available-for-sale marketable securities, Estimated Fair Value	$ 800.7	$ 707.2