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

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Schedule of Short-term Debt

The following table presents commercial paper outstanding, net of issuance discounts, as of September 30, 2018, and December 31, 2017:

	September 30, 2018		December 31, 2017
Ameren (parent)	$	413	$	383
Ameren Missouri	—		39
Ameren Illinois	108		62
Ameren Consolidated	$	521	$	484

The following table summarizes the borrowing activity and relevant interest rates under Ameren (parent)’s, Ameren Missouri’s, and Ameren Illinois’ commercial paper programs for the nine months ended September 30, 2018 and 2017:

	Ameren (parent)			Ameren Missouri			Ameren Illinois			Ameren Consolidated
2018
Average daily commercial paper outstanding at par value	$	431		$	81		$	117		$	629
Weighted-average interest rate	2.23		%	1.94		%	2.21		%	2.18		%
Peak commercial paper during period at par value(a)	$	543		$	481		$	442		$	1,295
Peak interest rate	2.45		%	2.42		%	2.55		%	2.55		%
2017
Average daily commercial paper outstanding at par value	$	669		$	7		$	78		$	754
Weighted-average interest rate	1.27		%	1.20		%	1.28		%	1.27		%
Peak commercial paper during period at par value(a)	$	841		$	64		$	193		$	948
Peak interest rate	1.50		%	1.41		%	1.50		%	1.50		%

(a) The timing of peak outstanding commercial paper issuances varies by company. Therefore, the sum of individual company peak amounts may not equal the Ameren Consolidated peak commercial paper issuances for the period.