Contingencies and Regulatory Matters (Tables)

9 Months Ended

Sep. 30, 2016

Commitments and Contingencies Disclosure [Abstract]

Recovery Balance of Each Regulatory Clause

The balance of each regulatory clause recovery on the balance sheet follows:

Regulatory Clause	Balance Sheet Line Item	September 30, 2016		December 31, 2015
		(in millions)
Rate CNP Compliance	Under recovered regulatory clause revenues	$	—	$	43
	Deferred over recovered regulatory clause revenues	23		—
Rate CNP PPA	Under recovered regulatory clause revenues	52		99
	Deferred under recovered regulatory clause revenues	87		—
Retail Energy Cost Recovery	Other regulatory liabilities, current	—		238
	Deferred over recovered regulatory clause revenues	134		—
Natural Disaster Reserve	Other regulatory liabilities, deferred	71		75

The balance of each regulatory clause recovery on the balance sheet follows:

Regulatory Clause	Balance Sheet Line Item	September 30, 2016		December 31, 2015
		(in millions)
Fuel Cost Recovery	Other regulatory liabilities, current	$	20	$	18
Purchased Power Capacity Recovery	Other regulatory liabilities, current	3		—
Purchased Power Capacity Recovery	Under recovered regulatory clause revenues	—		1
Environmental Cost Recovery	Other regulatory liabilities, current	5		—
Environmental Cost Recovery	Under recovered regulatory clause revenues	—		19
Energy Conservation Cost Recovery	Other regulatory liabilities, current	—		4
Energy Conservation Cost Recovery	Under recovered regulatory clause revenues	2		—

Current And Actual Cost Estimate for Kemper IGCC

Mississippi Power's Kemper IGCC 2010 project estimate, current cost estimate (which includes the impacts of the Mississippi Supreme Court's (Court) decision discussed herein under "Rate Recovery of Kemper IGCC Costs – 2013 MPSC Rate Order"), and actual costs incurred as of September 30, 2016 are as follows:

Cost Category	2010 Project Estimate(a)		Current Cost Estimate(b)			Actual Costs
	(in billions)
Plant Subject to Cost Cap(c)(e)	$	2.40	$	5.52		$	5.30
Lignite Mine and Equipment	0.21		0.23			0.23
CO2 Pipeline Facilities	0.14		0.11			0.11
AFUDC(d)	0.17		0.75			0.71
Combined Cycle and Related Assets Placed in Service – Incremental(e)	—		0.04			0.03
General Exceptions	0.05		0.10			0.09
Deferred Costs(e)	—		0.21			0.20
Additional DOE Grants(f)	—		(0.14		)	(0.14		)
Total Kemper IGCC	$	2.97	$	6.82		$	6.53

(a) The 2010 Project Estimate is the certificated cost estimate adjusted to include the certificated estimate for the CO₂ pipeline facilities approved in 2011 by the Mississippi PSC, as well as the lignite mine and equipment, AFUDC, and general exceptions.

(b) Amounts in the Current Cost Estimate include certain estimated post-in-service costs which are expected to be subject to the cost cap.

(c) The 2012 MPSC CPCN Order approved a construction cost cap of up to $2.88 billion, net of the Initial DOE Grants and excluding the Cost Cap Exceptions. The Current Cost Estimate and the Actual Costs include non-incremental operating and maintenance costs related to the combined cycle and associated common facilities placed in service in August 2014 that are subject to the $2.88 billion cost cap and exclude post-in-service costs for the lignite mine. See "Rate Recovery of Kemper IGCC Costs – 2013 MPSC Rate Order" herein for additional information. The Current Cost Estimate and the Actual Costs reflect 100% of the costs of the Kemper IGCC. See note (e) for additional information.

(d) Mississippi Power's 2010 Project Estimate included recovery of financing costs during construction rather than the accrual of AFUDC. This approach was not approved by the Mississippi PSC as described in "Rate Recovery of Kemper IGCC Costs – 2013 MPSC Rate Order." The Current Cost Estimate also reflects the impact of a settlement agreement with the wholesale customers for cost-based rates under FERC's jurisdiction. See "FERC Matters" herein for additional information.

(e) Non-capital Kemper IGCC-related costs incurred during construction were initially deferred as regulatory assets. Some of these costs are now included in rates and are being recognized through income; however, such costs continue to be included in the Current Cost Estimate and the Actual Costs at September 30, 2016. The wholesale portion of debt carrying costs, whether deferred or recognized through income, is not included in the Current Cost Estimate and the Actual Costs at September 30, 2016. See "Rate Recovery of Kemper IGCC Costs – Regulatory Assets and Liabilities" herein for additional information.

(f) On April 8, 2016, Mississippi Power received approximately $137 million in additional grants from the DOE for the Kemper IGCC (Additional DOE Grants), which are expected to be used to reduce future rate impacts for customers.