Equity Equity (Changes in Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Balance at December 31:	$ (521.0)
Other comprehensive income before reclassifications	(100.0)
Amounts reclassified from accumulated other comprehensive income	19.9
Tax (expense) benefit	(6.1)
Balance at March 31:	(607.2)
Cash flow hedges and marketable securities [Member]
Balance at December 31:	(1.4)
Other comprehensive income before reclassifications	(11.5)
Amounts reclassified from accumulated other comprehensive income	3.1
Tax (expense) benefit	(0.2)
Balance at March 31:	(10.0)
Pension and OPEB Adjustments [Member]
Balance at December 31:	(964.2)
Other comprehensive income before reclassifications	16.3
Amounts reclassified from accumulated other comprehensive income	16.8
Tax (expense) benefit	(5.9)
Balance at March 31:	(937.0)
Foreign Currency Gain (Loss) [Member]
Balance at December 31:	444.6
Other comprehensive income before reclassifications	(104.8)
Amounts reclassified from accumulated other comprehensive income	0
Tax (expense) benefit	0
Balance at March 31:	$ 339.8