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

6 Months Ended

Jun. 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 June 30, 2014, and December 31, 2013. Ameren Illinois established a commercial paper program in May 2014.

	June 30, 2014		December 31, 2013
Ameren (parent)	$	503	$	368
Ameren Missouri	185		—
Ameren Illinois	105		—
Ameren Consolidated	$	793	$	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 six months ended June 30, 2014, and 2013:

	Ameren (parent)			Ameren Missouri			Ameren Illinois			Ameren Consolidated
2014
Average daily commercial paper outstanding	$	328		$	146		$	242		$	607
Weighted-average interest rate	0.32		%	0.31		%	0.32		%	0.32		%
Peak commercial paper during period(a)	$	503		$	495		$	300		$	907
Peak interest rate	0.35		%	0.70		%	0.34		%	0.70		%
2013
Average daily commercial paper outstanding	$	13		$	—		$	—		$	13
Weighted-average interest rate	0.54		%	—		%	—		%	0.54		%
Peak commercial paper during period(a)	$	78		$	—		$	—		$	78
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.