Derivative Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2014

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Open Gross Derivative Volumes By Commodity Type

The following table presents open gross commodity contract volumes by commodity type for derivative assets and liabilities as of June 30, 2014, and December 31, 2013. As of June 30, 2014, these contracts ran through October 2017, October 2019, May 2032, and October 2016 for fuel oils, natural gas, power, and uranium, respectively.

	Quantity (in millions, except as indicated)
	2014			2013
Commodity	Ameren Missouri	Ameren Illinois	Ameren	Ameren Missouri	Ameren Illinois	Ameren
Fuel oils (in gallons)(a)	51	(b)	51	66	(b)	66
Natural gas (in mmbtu)	25	101	126	28	108	136
Power (in megawatthours)	1	11	12	3	11	14
Uranium (pounds in thousands)	627	(b)	627	796	(b)	796

(a) Fuel oils consist of ultra-low-sulfur diesel, on-highway diesel, and crude oil.

(b) Not applicable.

Derivative Instruments Carrying Value

The following table presents the carrying value and balance sheet location of all derivative commodity contracts, none of which were designated as hedging instruments, as of June 30, 2014, and December 31, 2013:

	Balance Sheet Location	Ameren  Missouri		Ameren  Illinois		Ameren
2014
Fuel oils	Other current assets	$	5	$	—	$	5
	Other assets	2		—		2
Natural gas	Other current assets	1		3		4
	Other assets	—		1		1
Power	Other current assets	22		—		22
	Total assets	$	30	$	4	$	34
Fuel oils	Other current liabilities	$	2	$	—	$	2
	Other deferred credits and liabilities	1		—		1
Natural gas	Other current liabilities	4		16		20
	Other deferred credits and liabilities	2		8		10
Power	Other current liabilities	6		7		13
	Other deferred credits and liabilities	—		96		96
Uranium	Other current liabilities	5		—		5
	Other deferred credits and liabilities	2		—		2
	Total liabilities	$	22	$	127	$	149
2013
Fuel oils	Other current assets	$	6	$	—	$	6
	Other assets	3		—		3
Natural gas	Other current assets	1		1		2
Power	Other current assets	23		—		23
	Total assets	$	33	$	1	$	34
Fuel oils	Other current liabilities	$	2	$	—	$	2
	Other deferred credits and liabilities	1		—		1
Natural gas	Other current liabilities	5		27		32
	Other deferred credits and liabilities	6		19		25
Power	Other current liabilities	4		9		13
	Other deferred credits and liabilities	—		99		99
Uranium	Other current liabilities	5		—		5
	Other deferred credits and liabilities	1		—		1
	Total liabilities	$	24	$	154	$	178

Cumulative Pretax Net Gains (Losses) On All Derivative Instruments In OCI

The following table presents the cumulative amount of pretax net gains (losses) on all derivative instruments deferred as regulatory assets or regulatory liabilities as of June 30, 2014, and December 31, 2013:

	Ameren Missouri			Ameren Illinois			Ameren
2014
Fuel oils derivative contracts(a)	$	3		$	—		$	3
Natural gas derivative contracts(b)	(5		)	(20		)	(25		)
Power derivative contracts(c)	16			(103		)	(87		)
Uranium derivative contracts(d)	(7		)	—			(7		)
2013
Fuel oils derivative contracts	$	2		$	—		$	2
Natural gas derivative contracts	(10		)	(45		)	(55		)
Power derivative contracts	19			(108		)	(89		)
Uranium derivative contracts	(6		)	—			(6		)

(a) Represents net gains on fuel oils derivative contracts at Ameren Missouri. These contracts are a partial hedge of Ameren Missouri’s transportation costs for coal through December 2017, as of June 30, 2014. Current gains deferred as regulatory liabilities include $2 million and $2 million at Ameren and Ameren Missouri, respectively, as of June 30, 2014. Current losses deferred as regulatory assets include $1 million and $1 million at Ameren and Ameren Missouri, respectively, as of June 30, 2014.

(b) Represents net losses associated with natural gas derivative contracts. These contracts are a partial hedge of natural gas requirements through October 2019 at Ameren and Ameren Missouri and through October 2017, at Ameren Illinois, in each case as of June 30, 2014. Current gains deferred as regulatory liabilities include $4 million, $1 million, and $3 million at Ameren, Ameren Missouri and Ameren Illinois, respectively, as of June 30, 2014. Current losses deferred as regulatory assets include $20 million, $4 million, and $16 million at Ameren, Ameren Missouri and Ameren Illinois, respectively, as of June 30, 2014.

(c) Represents net gains (losses) associated with power derivative contracts. These contracts are a partial hedge of power price requirements through May 2032 at Ameren and Ameren Illinois and through December 2015 at Ameren Missouri, in each case as of June 30, 2014. Current gains deferred as regulatory liabilities include $22 million and $22 million at Ameren and Ameren Missouri, respectively, as of June 30, 2014. Current losses deferred as regulatory assets include $13 million, $6 million, and $7 million at Ameren, Ameren Missouri and Ameren Illinois, respectively, as of June 30, 2014.

(d) Represents net losses on uranium derivative contracts at Ameren Missouri. These contracts are a partial hedge of Ameren Missouri’s uranium requirements through December 2016, as of June 30, 2014. Current losses deferred as regulatory assets include $5 million and $5 million at Ameren and Ameren Missouri, respectively, as of June 30, 2014.

Offsetting Derivative Assets and Liabilities

The following table provides the recognized gross derivative balances and the net amounts of those derivatives subject to an enforceable master netting arrangement or similar agreement as of June 30, 2014, and December 31, 2013:

			Gross Amounts Not Offset in the Balance Sheet
Commodity Contracts Eligible to be Offset	Gross Amounts Recognized in the Balance Sheet		Derivative Instruments		Cash Collateral Received/Posted(a)		Net Amount
2014
Assets:
Ameren Missouri	$	30	$	9	$	—	$	21
Ameren Illinois	4		3		—		1
Ameren	$	34	$	12	$	—	$	22
Liabilities:
Ameren Missouri	$	22	$	9	$	10	$	3
Ameren Illinois	127		3		—		124
Ameren	$	149	$	12	$	10	$	127
2013
Assets:
Ameren Missouri	$	33	$	9	$	—	$	24
Ameren Illinois	1		1		—		—
Ameren	$	34	$	10	$	—	$	24
Liabilities:
Ameren Missouri	$	24	$	9	$	9	$	6
Ameren Illinois	154		1		15		138
Ameren	$	178	$	10	$	24	$	144

(a) Cash collateral received reduces gross asset balances and is included in “Other current liabilities” and “Other deferred credits and liabilities” on the balance sheet. Cash collateral posted reduces gross liability balances and is included in “Other current assets” and “Other assets” on the balance sheet.

Derivative Instruments With Credit Risk-Related Contingent Features

The additional collateral required is the net liability position allowed under the master trading and netting agreements, assuming (1) the credit risk-related contingent features underlying these agreements were triggered on June 30, 2014, or December 31, 2013, respectively, and (2) those counterparties with rights to do so requested collateral.

	Aggregate Fair Value of Derivative Liabilities(a)		Cash Collateral Posted		Potential Aggregate Amount of Additional  Collateral Required(b)
2014
Ameren Missouri	$	60	$	2	$	53
Ameren Illinois	65		—		59
Ameren	$	125	$	2	$	112
2013
Ameren Missouri	$	70	$	2	$	67
Ameren Illinois	75		15		55
Ameren	$	145	$	17	$	122

(a) Prior to consideration of master trading and netting agreements and including NPNS and accrual contract exposures.

(b) As collateral requirements with certain counterparties are based on master trading and netting agreements, the aggregate amount of additional collateral required to be posted is determined after consideration of the effects of such agreements.