Notes Payable - Schedule of Notes Payable (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Short-term Debt [Line Items]
Total notes payable	$ 383		$ 221
Plus - current maturities of long-term debt	0		0
Total notes payable and current maturities of long-term debt	383		221
Notes payable, weighted average interest rate	0.20%		0.10%
Current maturities of long-term debt, weighted average interest rate	0.00%		0.00%
Total notes payable and current maturities of long-term debt, weighted average interest rate	0.20%		0.10%
Commercial paper
Short-term Debt [Line Items]
Total notes payable	381	[1]	221	[1]
Notes payable, weighted average interest rate	0.20%	[1]	0.10%	[1]
$200.0 European revolving credit facility, due March 13, 2014
Short-term Debt [Line Items]
Total notes payable	0	[2]	0	[2]
Notes payable, weighted average interest rate	0.00%	[2]	0.00%	[2]
Sigma-Aldrich Korea limited credit facility, Due June 30, 2013
Short-term Debt [Line Items]
Total notes payable	0	[3]	0	[3]
Notes payable, weighted average interest rate	0.00%	[3]	0.00%	[3]
Sigma-Aldrich Japan credit facilities
Short-term Debt [Line Items]
Total notes payable	0	[4]	0	[4]
Notes payable, weighted average interest rate	0.00%	[4]	0.00%	[4]
Other short-term credit facilities
Short-term Debt [Line Items]
Total notes payable	$ 2	[5]	$ 0	[5]
Notes payable, weighted average interest rate	1.50%	[5]	0.00%	[5]

[1] On May 10, 2012, the Company entered into a new $600 five-year revolving credit facility with a syndicate of banks in the U.S. that supports the Company's commercial paper program. The new facility will mature on May 9, 2017, and replaces a $450 revolving credit facility that was scheduled to mature on December 11, 2012. At December 31, 2012 and December 31, 2011, the Company did not have any borrowings outstanding under these facilities. However, the amount available under the facilities is reduced by the amount of commercial paper outstanding. The new facility contains financial covenants that require the maintenance of a ratio of consolidated debt to total capitalization of no more than 65.0 percent and an aggregate amount of subsidiary debt plus consolidated secured debt of no more than 25.0 percent of total net worth. The Company's total consolidated debt as a percentage of total capitalization and aggregate amount of subsidiary debt plus consolidated secured debt as a percentage of total net worth, as defined in the underlying credit agreement, was 22.1 percent and 0.1 percent, respectively, at December 31, 2012.

[2] Facility contains financial covenants that require the maintenance of consolidated net worth of at least $750, a ratio of consolidated debt to total capitalization of no more than 55.0 percent and an aggregate amount of subsidiary debt plus consolidated secured debt of no more than 25.0 percent of total net worth. The Company's consolidated net worth, consolidated debt as a percentage of total capitalization and aggregate amount of subsidiary debt plus consolidated secured debt as a percentage of total net worth, as defined in the underlying credit agreement, were $2,405, 22.1 percent and 0.1 percent, respectively, at December 31, 2012.

[3] There were no outstanding borrowings under this facility, which has a total commitment of 20 billion Korean Won ($19), at December 31, 2012.

[4] Sigma-Aldrich Japan has two credit facilities having a total commitment of 2 billion Japanese Yen ($23), with one facility due April 30, 2013 and the other representing a line of credit with no expiration. There were no borrowings under the facilities at December 31, 2012.

[5] There were $2 in borrowings under these facilities, which have total commitments in U.S. Dollar equivalents of $3, at December 31, 2012.