EarningsPer Share Data Convertible Debt (Details)	6 Months Ended
	Jun. 30, 2015 $ / shares
3.75% Convertible Senior Subordinated Notes, due 2025 [Member]
treasury stock method average share price to include dilutive securities	$ 26.56
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	77.00
3.75% Convertible Senior Subordinated Notes Due 2042 [Member]
treasury stock method average share price to include dilutive securities	77.00
3.5% Convertible senior subordinated debt [Domain]
treasury stock method average share price to include dilutive securities	$ 70.00