Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Net income	$ 205		$ 296
Other comprehensive income (loss), net of tax
Reclassification of actuarial losses to net benefit cost (net of income tax of $2 and $1 for the three months ended March 31, 2015 and 2014, respectively)	3		1
Cash flow hedges, net of tax
Net derivative instrument gain arising during the period (net of income tax of $1 for the three months ended March 31, 2015)	2		4
Reclassification of realized derivative instrument gain to net income			(4)
Cash flow hedges, net	2	[1]		[1]
Other comprehensive income, net of tax	5	[1]	1	[1]
Retirement benefit plans, net	3	[1]	1	[1]
Comprehensive income	210		297
Less comprehensive income attributable to noncontrolling interest	12		12
Comprehensive income attributable to AGL Resources Inc.	$ 198		$ 285

[1] All amounts are net of income taxes. Amounts in parentheses indicate debits to accumulated other comprehensive loss.