Derivatives and Hedge Accounting Activities (Volume of Derivative Activity) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015
Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate	$ 2,550
Current Derivative Contract | Natural Gas | Fixed Price
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	55,000,000,000	[1]
Current Derivative Contract | Natural Gas | Basis
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	224,000,000,000
Current Derivative Contract | Electricity | Fixed Price
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh)	13,610,507
Current Derivative Contract | Electricity | Financial Transmission Rights
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh)	14,994,541
Current Derivative Contract | Capacity
Derivative Instruments, Gain (Loss) [Line Items]
Capacity (MW)	15,250
Current Derivative Contract | Liquids
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	77,280,000	[2]
Noncurrent Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate	4,000
Noncurrent Derivative Contract | Natural Gas | Fixed Price
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	10,000,000,000	[1]
Noncurrent Derivative Contract | Natural Gas | Basis
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	558,000,000,000
Noncurrent Derivative Contract | Electricity | Fixed Price
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh)	7,505,325
Noncurrent Derivative Contract | Electricity | Financial Transmission Rights
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh)	0
Noncurrent Derivative Contract | Capacity
Derivative Instruments, Gain (Loss) [Line Items]
Capacity (MW)	3,050
Noncurrent Derivative Contract | Liquids
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	2,016,000	[2]
Virginia Electric and Power Company | Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate	1,000
Virginia Electric and Power Company | Current Derivative Contract | Natural Gas | Fixed Price
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	12,000,000,000	[1]
Virginia Electric and Power Company | Current Derivative Contract | Natural Gas | Basis
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	84,000,000,000
Virginia Electric and Power Company | Current Derivative Contract | Electricity | Financial Transmission Rights
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh)	13,486,569
Virginia Electric and Power Company | Current Derivative Contract | Capacity
Derivative Instruments, Gain (Loss) [Line Items]
Capacity (MW)	15,250
Virginia Electric and Power Company | Noncurrent Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate	750
Virginia Electric and Power Company | Noncurrent Derivative Contract | Natural Gas | Fixed Price
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	0	[1]
Virginia Electric and Power Company | Noncurrent Derivative Contract | Natural Gas | Basis
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	493,000,000,000
Virginia Electric and Power Company | Noncurrent Derivative Contract | Electricity | Financial Transmission Rights
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh)	0
Virginia Electric and Power Company | Noncurrent Derivative Contract | Capacity
Derivative Instruments, Gain (Loss) [Line Items]
Capacity (MW)	3,050
Dominion Gas Holdings, LLC | Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate	0
Dominion Gas Holdings, LLC | Current Derivative Contract | Natural Gas | Fixed Price
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	7,000,000,000
Dominion Gas Holdings, LLC | Current Derivative Contract | Natural Gas | Basis
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	8,000,000,000
Dominion Gas Holdings, LLC | Current Derivative Contract | Liquids
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	72,912,000
Dominion Gas Holdings, LLC | Noncurrent Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate	$ 250
Dominion Gas Holdings, LLC | Noncurrent Derivative Contract | Natural Gas | Fixed Price
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	0
Dominion Gas Holdings, LLC | Noncurrent Derivative Contract | Natural Gas | Basis
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	0
Dominion Gas Holdings, LLC | Noncurrent Derivative Contract | Liquids
Derivative Instruments, Gain (Loss) [Line Items]
Volume of natural gas (cf)/ liquids (gallons)	0

[1] Includes options.

[2] Includes NGLs and oil.