Commitments And Contingencies (Callaway Nuclear Energy Center) (Details)	12 Months Ended
	Dec. 31, 2016 USD ($)
Commitments and Contingencies [Line Items]
Insurance aggregate maximum coverage	$ 13,361,000,000	[1]
Insurance maximum coverage per incident	127,000,000
Threshold Amount For Retrospective Insurance Assessment For Covered Loss Under Public Liability And Nuclear Worker Liability Insurance Policy	375,000,000
Annual payment in the event of an incident at any licensed commercial reactor	19,000,000
Aggregate maximum assessment per incident under Price-Anderson liability provisions of Atomic Energy Act	127,000,000
Maximum annual payment to be paid in a calendar year per reactor incident under liability provisions of Atomic Energy Act	19,000,000
Amount of coverage in excess of primary property liability coverage	2,300,000,000.0
Amount of weekly indemnity coverage commencing eight weeks after power outage	$ 4,500,000
Number of weeks of coverage after the first eight weeks of an outage	1 year
Amount of additional weekly indemnity coverage commencing after initial indemnity coverage	$ 3,600,000
Number of additional weeks after initial indemnity coverage for power outage, minimum	1 year 4 months 10 days
Amount of weekly indemnity coverage thereafter not exceeding policy limit	$ 490,000,000
Number Of Years The Limit Of Liability And The Maximum Potential Annual Payments Are Adjusted	5 years
Aggregate nuclear power industry insurance policy limit for losses from terrorist attacks within twelve month period	$ 3,240,000,000
Public Liability And Nuclear Worker Liability - American Nuclear Insurers
Commitments and Contingencies [Line Items]
Insurance aggregate maximum coverage	375,000,000	[2]
Insurance maximum coverage per incident	0
Public Liability And Nuclear Worker Liability - Pool Participation
Commitments and Contingencies [Line Items]
Insurance aggregate maximum coverage	12,986,000,000	[3]
Insurance maximum coverage per incident	127,000,000	[4]
Property Damage - Nuclear Electric Insurance Ltd
Commitments and Contingencies [Line Items]
Insurance aggregate maximum coverage	2,710,000,000	[5]
Insurance maximum coverage per incident	30,000,000	[6]
Replacement Power - Nuclear Electric Insurance Ltd
Commitments and Contingencies [Line Items]
Insurance aggregate maximum coverage	490,000,000	[7]
Insurance maximum coverage per incident	7,000,000	[6]
Sub-limit of Amount of Weekly indemnity Coverage Thereafter Not Exceeding Policy Limit for Non-Nuclear Events	328,000,000
Property Damage European Mutual Association for Nuclear Insurance
Commitments and Contingencies [Line Items]
Insurance aggregate maximum coverage	450,000,000	[7]
Amount of primary property liability coverage	450,000,000
Property Damage
Commitments and Contingencies [Line Items]
Insurance aggregate maximum coverage	3,160,000,000
Insurance maximum coverage per incident	30,000,000
Radiation Event
Commitments and Contingencies [Line Items]
Insurance aggregate maximum coverage	2,710,000,000
Non-radiation event
Commitments and Contingencies [Line Items]
Insurance aggregate maximum coverage	2,300,000,000
Aggregate nuclear power industry insurance policy limit for losses from terrorist attacks within twelve month period	$ 1,830,000,000

[1] Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. A company could be assessed up to $127 million per incident for each licensed reactor it operates, with a maximum of $19 million per incident to be paid in a calendar year for each reactor. This limit is subject to change to account for the effects of inflation and changes in the number of licensed reactors.

[2] Effective January 1, 2017, limit was increased to $450 million

[3] Provided through mandatory participation in an industrywide retrospective premium assessment program.

[4] Retrospective premium under the Price-Anderson Act. This is subject to retrospective assessment with respect to a covered loss in excess of $375 million in the event of an incident at any licensed United States commercial reactor, payable at $19 million per year.

[5] NEIL provides $2.71 billion in property damage, decontamination, and premature decommissioning insurance for radiation events. NEIL provides $2.3 billion in property damage for nonradiation events.

[6] All NEIL-insured plants could be subject to assessments should losses exceed the accumulated funds from NEIL

[7] European Mutual Association for Nuclear Insurance provides $450 million in excess of the $2.71 billion and $2.3 billion property coverage for radiation and nonradiation events, respectively, provided by NEIL.