Regulatory Assets and Liabilities (Schedule of Regulatory Assets and Liabilities) (Details) - USD ($)	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Total current regulatory assets	$ 14,400,000	$ 44,200,000
Total non-current regulatory assets	179,900,000	167,500,000
Total regulatory assets	194,300,000	211,700,000
Total current regulatory liabilities	24,400,000	4,400,000
Total non-current regulatory liabilities	127,000,000	124,100,000
Total regulatory liabilities	151,400,000	128,500,000
Energy efficiency program [Member]
Total current regulatory liabilities	9,200,000	0
Competitive bidding [Member]
Total current regulatory liabilities	9,100,000	0
Transmission costs [Member]
Total current regulatory liabilities	3,700,000	2,900,000
Reconciliation rider [Member]
Total current regulatory liabilities	2,100,000	0
Other miscellaneous [Member]
Total current regulatory liabilities	300,000	1,500,000
Estimated costs of removal - regulated property [Member]
Total non-current regulatory liabilities	121,800,000	119,300,000
Postretirement benefits [Member]
Total non-current regulatory liabilities	5,200,000	4,800,000
THE DAYTON POWER AND LIGHT COMPANY [Member]
Total current regulatory assets	14,400,000	44,200,000
Total non-current regulatory assets	179,900,000	167,500,000
Total regulatory assets	194,300,000	211,700,000
Total current regulatory liabilities	24,400,000	4,400,000
Total non-current regulatory liabilities	127,000,000	124,100,000
Total regulatory liabilities	151,400,000	128,500,000
THE DAYTON POWER AND LIGHT COMPANY [Member] \| Energy efficiency program [Member]
Total current regulatory liabilities	9,200,000	0
THE DAYTON POWER AND LIGHT COMPANY [Member] \| Competitive bidding [Member]
Total current regulatory liabilities	9,100,000	0
THE DAYTON POWER AND LIGHT COMPANY [Member] \| Transmission costs [Member]
Total current regulatory liabilities	3,700,000	2,900,000
THE DAYTON POWER AND LIGHT COMPANY [Member] \| Reconciliation rider [Member]
Total current regulatory liabilities	2,100,000	0
THE DAYTON POWER AND LIGHT COMPANY [Member] \| Other miscellaneous [Member]
Total current regulatory liabilities	300,000	1,500,000
THE DAYTON POWER AND LIGHT COMPANY [Member] \| Estimated costs of removal - regulated property [Member]
Total non-current regulatory liabilities	121,800,000	119,300,000
THE DAYTON POWER AND LIGHT COMPANY [Member] \| Postretirement benefits [Member]
Total non-current regulatory liabilities	$ 5,200,000	4,800,000
Fuel and purchased power recovery costs [Member]
Type of Recovery	A
Amortization Through	2016
Total current regulatory assets	$ 13,900,000	16,300,000
Fuel and purchased power recovery costs [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	A
Amortization Through	2016
Total current regulatory assets	$ 13,900,000	16,300,000
Economic development costs [Member]
Type of Recovery	A
Amortization Through	2016
Total current regulatory assets	$ 500,000	2,100,000
Economic development costs [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	A
Amortization Through	2016
Total current regulatory assets	$ 500,000	2,100,000
Deferred storm costs [Member]
Type of Recovery	B
Amortization Through	2015
Total current regulatory assets	$ 0	22,300,000
Deferred storm costs [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	B
Amortization Through	2015
Total current regulatory assets	$ 0	22,300,000
Energy efficiency program [Member]
Type of Recovery	A
Amortization Through	2016
Total current regulatory assets	$ 0	1,800,000
Energy efficiency program [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	A
Amortization Through	2016
Total current regulatory assets	$ 0	1,800,000
Other miscellaneous [Member]
Type of Recovery	A
Amortization Through	2016
Total current regulatory assets	$ 0	1,700,000
Other miscellaneous [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	A
Amortization Through	2016
Total current regulatory assets	$ 0	1,700,000
Pension benefits [Member]
Type of Recovery	B
Amortization Through	Ongoing
Total non-current regulatory assets	$ 91,600,000	99,600,000
Pension benefits [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	B
Amortization Through	Ongoing
Total non-current regulatory assets	$ 91,600,000	99,600,000
Deferred recoverable income taxes [Member]
Type of Recovery	B/C
Amortization Through	Ongoing
Total non-current regulatory assets	$ 36,400,000	43,100,000
Deferred recoverable income taxes [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	B/C
Amortization Through	Ongoing
Total non-current regulatory assets	$ 36,400,000	43,100,000
Fuel costs [Member]
Type of Recovery	B
Amortization Through	Undetermined
Total non-current regulatory assets	$ 12,700,000	0
Fuel costs [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	B
Amortization Through	Undetermined
Total non-current regulatory assets	$ 12,700,000	0
Unrecovered OVEC charges [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 10,500,000	0
Unrecovered OVEC charges [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 10,500,000	0
Unamortized loss on reacquired debt [Member]
Type of Recovery	B
Amortization Through	Various
Total non-current regulatory assets	$ 9,000,000	9,900,000
Unamortized loss on reacquired debt [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	B
Amortization Through	Various
Total non-current regulatory assets	$ 9,000,000	9,900,000
Smart grid and advanced metering infrastructure costs [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 7,300,000	6,600,000
Smart grid and advanced metering infrastructure costs [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 7,300,000	6,600,000
Generation separation costs [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 3,900,000	1,600,000
Generation separation costs [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Amortization Through	Undetermined
Total non-current regulatory assets	$ 3,900,000	1,600,000
Retail settlement system costs [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 3,100,000	3,100,000
Retail settlement system costs [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 3,100,000	3,100,000
Consumer education campaign [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 3,000,000	3,000,000
Consumer education campaign [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 3,000,000	3,000,000
Rate case costs [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 1,900,000	0
Rate case costs [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	D
Total non-current regulatory assets	$ 1,900,000	0
Other miscellaneous [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 500,000	600,000
Other miscellaneous [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Type of Recovery	D
Amortization Through	Undetermined
Total non-current regulatory assets	$ 500,000	$ 600,000

This element represents the type of recovery for each regulatory asset or liability.

No definition available.

Name:	dpl_RegulatoryAssetsTypeOfRecovery
Namespace Prefix:	dpl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382

+ Details

Name:	us-gaap_RegulatoryAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost.

+ References

+ Details

Name:	us-gaap_RegulatoryAssetsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer.

+ References

+ Details

Name:	us-gaap_RegulatoryAssetsNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The end date for recovery of the individual regulatory current asset in a schedule of regulatory current assets.

+ References

+ Details

Name:	us-gaap_RegulatoryCurrentAssetEndDateForRecovery
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 405
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394

+ Details

Name:	us-gaap_RegulatoryLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period.

+ References

+ Details

Name:	us-gaap_RegulatoryLiabilityCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.24)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_RegulatoryLiabilityNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant