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

3 Months Ended

Mar. 31, 2015

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 March 31, 2015, and December 31, 2014.

	March 31, 2015		December 31, 2014
Ameren (parent)	$	815	$	585
Ameren Missouri	140		97
Ameren Illinois	—		32
Ameren Consolidated	$	955	$	714

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 three months ended March 31, 2015 and 2014. Ameren Illinois established a commercial paper program in May 2014.

	Ameren (parent)			Ameren Missouri			Ameren Illinois			Ameren Consolidated
2015
Average daily commercial paper outstanding	$	691		$	151		$	10		$	852
Weighted-average interest rate	0.55		%	0.49		%	0.44		%	0.53		%
Peak commercial paper during period(a)	$	815		$	243		$	39		$	955
Peak interest rate	0.70		%	0.60		%	0.60		%	0.70		%
2014
Average daily commercial paper outstanding	$	339		$	200		$	—		$	539
Weighted-average interest rate	0.45		%	0.45		%	—		%	0.45		%
Peak commercial paper during period(a)	$	452		$	290		$	—		$	700
Peak interest rate	0.75		%	0.70		%	—		%	0.75		%

(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.