Property, Plant and Equipment 1 (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 7,299,609	$ 7,078,253
Less accumulated depreciation and amortization	1,573,273	1,373,794
Net property, plant and equipment	5,726,336	5,704,459
Regulated [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,324,220	5,193,041
Less accumulated depreciation and amortization	1,219,017	1,074,161
Net property, plant and equipment	4,105,203	4,118,880
Nonregulated [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,975,389	1,885,212
Less accumulated depreciation and amortization	354,256	299,633
Net property, plant and equipment	1,621,133	1,585,579
Distribution plant [Member] | Regulated [Member]
Property, Plant and Equipment [Line Items]
Life minimum	9
Life maximum	60
Regulated Operations	1,042,857	1,001,032
Distribution plant [Member] | Nonregulated [Member]
Property, Plant and Equipment [Line Items]
Life minimum	5
Life maximum	40
Non-regulated Operations	60,466	59,749
Gathering and processing plant [Member] | Regulated [Member]
Property, Plant and Equipment [Line Items]
Life minimum	26
Life maximum	26
Regulated Operations	166,990	183,548
Gathering and processing plant [Member] | Nonregulated [Member]
Property, Plant and Equipment [Line Items]
Life minimum	1
Life maximum	50
Non-regulated Operations	1,839,571	1,740,725
Transmission plant [Member] | Regulated [Member]
Property, Plant and Equipment [Line Items]
Life minimum	5
Life maximum	46
Regulated Operations	2,321,009	2,239,762
General - LNG | Regulated [Member]
Property, Plant and Equipment [Line Items]
Life minimum	5
Life maximum	40
Regulated Operations	1,118,791	1,117,418
Underground storage plant [Member] | Regulated [Member]
Property, Plant and Equipment [Line Items]
Life minimum	5
Life maximum	46
Regulated Operations	321,920	314,744
General plant and other | Regulated [Member]
Property, Plant and Equipment [Line Items]
Life minimum	3
Life maximum	50
Regulated Operations	304,385	283,737
General plant and other | Nonregulated [Member]
Property, Plant and Equipment [Line Items]
Life minimum	3
Life maximum	29
Non-regulated Operations	19,758	17,274
Construction work in progress
Property, Plant and Equipment [Line Items]
Non-regulated Operations	55,594
Construction work in progress | Regulated [Member]
Property, Plant and Equipment [Line Items]
Regulated Operations	48,268	52,800
Construction work in progress | Nonregulated [Member]
Property, Plant and Equipment [Line Items]
Non-regulated Operations		$ 67,464