Debt (Details)	0 Months Ended	3 Months Ended	9 Months Ended					0 Months Ended					0 Months Ended
	Jun. 30, 2014 EUR (€)	Sep. 30, 2014 Commercial paper [Member] USD ($)	Sep. 30, 2014 Commercial paper [Member] USD ($)	Dec. 31, 2013 Commercial paper [Member] USD ($)	Sep. 30, 2014 3.50% debt securities due September 2015 [Member] Notes Payable, Other Payables [Member]	Aug. 12, 2014 3.50% notes due 2024 [Member] Notes Payable, Other Payables [Member] USD ($)	May 20, 2014 3.50% notes due 2024 [Member] Notes Payable, Other Payables [Member] USD ($)	Jul. 01, 2014 Debt Securities 6.25 Percent, Due 2014 [Member] EUR (€)	Jul. 01, 2014 Debt Securities 6.25 Percent, Due 2014 [Member] Notes Payable, Other Payables [Member]	Jun. 30, 2014 Debt Securities 6.25 Percent, Due 2014 [Member] Notes Payable, Other Payables [Member] EUR (€)	May 20, 2014 4.60% notes due 2044 [Member] Notes Payable, Other Payables [Member] USD ($)	May 07, 2014 2.875% notes due 2026 [Member] Notes Payable, Other Payables [Member] EUR (€)	Jul. 01, 2014 Debt Securities 6.25 Percent, Due 2014 [Member] EUR (€)	Sep. 30, 2014 Short-term debt and current portion of long-term debt [Member] 3.50% debt securities due September 2015 [Member] USD ($)
Debt Instrument [Line Items]
Total debt		$ 50,000,000	$ 50,000,000	$ 0
Weighted average commercial paper outstanding		360,000,000	338,000,000
Weighted-average interest rates (as a percent)		0.31%	0.34%
Debt Instrument, Face Amount						350,000,000	250,000,000			500,000,000	550,000,000	500,000,000		600,000,000
Debt interest rate percentage					3.50%	3.50%	3.50%		6.25%	6.25%	4.60%	2.875%
Repayments of Debt								531,000,000
Payments for Deposits Applied to Debt Retirements	531,000,000
Repayment of debt													€ 500,000,000