Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income	$ 35	$ 19	$ 174	$ 153
Retirement benefit plans
Reclassification of losses and prior service costs to net benefit cost (net of income tax of $3 and $4 for the three and six months ended June 30, 2012)	7	0	8	0
Retirement benefit plans, net	7	0	8	0
Cash flow hedges, net of tax
Net derivative instrument losses (gains) arising during the period (net of income tax of $3 and $1 for the three and six months ended June 30, 2012)	4	0	2	(1)
Cash flow hedges, net	4	0	2	(1)
Other comprehensive income (loss), net of tax	11	0	10	(1)
Comprehensive income	46	19	184	152
Less comprehensive income attributable to noncontrolling interest	(1)	(1)	(10)	(11)
Comprehensive income attributable to AGL Resources Inc.	$ 45	$ 18	$ 174	$ 141