EarningsPer Share Data Convertible Debt (Details) (USD $)	3 Months Ended
	Mar. 31, 2013
3.75% Convertible Senior Subordinated Notes, due 2025 [Member]
treasury stock method average share price to include dilutive securities	$ 27.11
4.00% Junior Subordinated Convertible Debentures, due 2033 [Member]
treasury stock method average share price to include dilutive securities	$ 40.82
3.25% Convertible Senior Debentures, Due 2035 [Member]
treasury stock method average share price to include dilutive securities	$ 78.49
3.75% Convertible Senior Subordinated Notes Due 2042 [Member]
treasury stock method average share price to include dilutive securities	$ 41.26