Short-Term Debt And Liquidity Short-Term Debt and Liquidity (Tables)

9 Months Ended

Sep. 30, 2014

Schedule of Commercial paper [Abstract]

Schedule of Short-term Debt [Table Text Block]

The following table presents commercial paper outstanding at Ameren (parent), Ameren Missouri and Ameren Illinois as of September 30, 2014, and December 31, 2013. Ameren Illinois established a commercial paper program in May 2014.

	September 30, 2014		December 31, 2013
Ameren (parent)	$	499	$	368
Ameren Missouri	65		—
Ameren Illinois	189		—
Ameren Consolidated	$	753	$	368

The following table summarizes the commercial paper activity and relevant interest rates under Ameren’s (parent), Ameren Missouri’s and Ameren Illinois’ commercial paper programs for the nine months ended September 30, 2014, and 2013:

	Ameren (parent)			Ameren Missouri			Ameren Illinois			Ameren Consolidated
2014
Average daily commercial paper outstanding	$	386		$	141		$	157		$	609
Weighted-average interest rate	0.36		%	0.38		%	0.31		%	0.35		%
Peak commercial paper during period(a)	$	531		$	495		$	300		$	907
Peak interest rate	0.75		%	0.70		%	0.34		%	0.75		%
2013
Average daily commercial paper outstanding	$	26		$	—		$	—		$	26
Weighted-average interest rate	0.52		%	—		%	—		%	0.52		%
Peak commercial paper during period(a)	$	92		$	—		$	—		$	92
Peak interest rate	0.85		%	—		%	—		%	0.85		%

(a) The timing of peak commercial paper issuances varies by company, and therefore the peak amounts presented by company might not equal the Ameren Consolidated peak commercial paper issuances for the period.