Short-Term Debt (Tables)

12 Months Ended

Dec. 31, 2011

Short-Term Debt (Tables) [Abstract]

Short-term notes payable balances and their corresponding weighted-average interest rates

Short-term notes payable balances and their corresponding weighted-average interest rates as of December 31 consist of:

	2011				2010
			Interest				Interest
Short-Term Debt	Balance		Rate		Balance		Rate
	(Millions of Dollars, except for percentages)
Commercial paper	$	669.9	0.27	%	$	657.9	0.30	%

Commercial paper

The following information relates to commercial paper for the years ended December 31:

	2011			2010
	(Millions of Dollars, except for percentages)
Maximum Short-Term Debt Outstanding	$	717.3		$	821.0
Average Short-Term Debt Outstanding	$	505.1		$	528.7
Weighted-Average Interest Rate	0.25		%	0.32		%