Significant Financing Transactions - (Commercial Paper, Bank Loans and Letters of Credit Outstanding) (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2014 Virginia Electric and Power Company	Sep. 30, 2014 Credit Facility 4 Billion		May 31, 2014 Credit Facility 4 Billion		May 01, 2014 Credit Facility 4 Billion		Sep. 30, 2014 Credit Facility 4 Billion Virginia Electric and Power Company		Jul. 31, 2014 Credit Facility 4 Billion Virginia Electric and Power Company		Jul. 01, 2014 Credit Facility 4 Billion Virginia Electric and Power Company		Sep. 30, 2014 Credit Facility 500 Million		Sep. 30, 2014 Credit Facility 500 Million Virginia Electric and Power Company
Line of Credit Facility [Line Items]
Facility Limit	$ 4,500,000,000	$ 1,500,000,000	$ 4,000,000,000	[1]	$ 4,000,000,000	[1]	$ 3,000,000,000	[1]	$ 1,250,000,000	[2]	$ 1,250,000,000.00	[1]	$ 1,000,000,000.0	[1]	$ 500,000,000	[3]	$ 250,000,000	[4]
Outstanding Commercial Paper	2,629,000,000	1,403,000,000	2,476,000,000	[1]					1,250,000,000	[2]					153,000,000	[3]	153,000,000	[4]
Outstanding Letters of Credit	31,000,000	0	0	[1]					0	[2]					31,000,000	[3]	0	[4]
Facility Capacity Available	1,840,000,000	97,000,000	1,524,000,000	[1]					0	[2]					316,000,000	[3]	97,000,000	[4]
Credit Facility, to support letters of credit			$ 1,500,000,000.0						$ 1,500,000,000.0

[1] In May 2014, this credit facility was amended and restated. The facility limit was increased from $3 billion to $4 billion and the maturity date was extended from September 2018 to April 2019. This credit facility can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $1.5 billion of letters of credit.

[2] In May 2014, this credit facility was amended and restated and the maturity date was extended from September 2018 to April 2019. This credit facility can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $1.5 billion (or the sub-limit, whichever is less) of letters of credit. Virginia Power's current sub-limit under this credit facility can be increased or decreased multiple times per year. In July 2014, Virginia Power increased its sub-limit from $1.0 billion to $1.25 billion.

[3] In May 2014, this credit facility was amended and restated and the maturity date was extended from September 2018 to April 2019. This credit facility can be used to support bank borrowings, commercial paper and letter of credit issuances.

[4] In May 2014, this credit facility was amended and restated and the maturity date was extended from September 2018 to April 2019. This credit facility can be used to support bank borrowings, commercial paper and letter of credit issuances. Virginia Power's current sub-limit under this credit facility can be increased or decreased multiple times per year.