Financing Arrangements (Narrative) (Details)	12 Months Ended		12 Months Ended						12 Months Ended
	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2011 Debt offering, four point eight five percent, due June Fifteen Two Thousand Twenty One [Member] USD ($)	Dec. 31, 2011 Debt Offering, Six Point One Two Five percent, due June Fifteen Two Thousand Eleven [Member] USD ($)	Dec. 31, 2011 Credit Facility maturing Aug 13 2012 [Member] USD ($)	Dec. 31, 2011 Credit Facility maturing June 28 2016 [Member] USD ($)	Dec. 31, 2010 Credit Facility maturing June 28 2016 [Member] USD ($)	Dec. 31, 2011 Letter of Credit Subfacility [Member] USD ($)	Dec. 31, 2011 Committed Credit Facility Brazil [Member] USD ($)	Dec. 31, 2011 Committed Credit Facility Brazil [Member] BRL
Debt Instrument [Line Items]
Long-term Debt, Fair Value	$ 2,670,000,000	$ 2,716,000,000
Debt Instrument, Face Amount			300,000,000	300,000,000
Maturity Date			Jun. 15, 2021	Jun. 15, 2011
Stated interest rate			4.85%	6.125%
Repurchase Of Notes, Purchase Price Percentage Of Principal Amount			101.00%
Line of Credit Facility, Expiration Date					August 13, 2012	June 28, 2016
Line of Credit Facility, Maximum Borrowing Capacity					1,350,000,000	1,725,000,000			373,000,000	700,000,000
Line of Credit Facility, Current Borrowing Capacity								200,000,000
Line of Credit Facility, Interest Rate Description						(1) 1.625% over LIBOR; (2) 0.625% over the prime rate;
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage						0.25%
Line of Credit Facility, Amount Outstanding						0	0		0
Line of Credit Facility, Covenant Compliance						We were in compliance with financial covenant requirements			The credit facility contains no financial covenants	The credit facility contains no financial covenants
Maximum rolling twelve month Leverage Ratio						3.25 to 1.0
Rolling twelve month Interest Coverate Ratio						3.0 to 1.0
Commitment Fees	$ 5,000,000