Earnings Per Share

6 Months Ended

Jun. 30, 2011

Earnings Per Common Share Attributable To Questar [Abstract]

Earnings Per Share

Note 4 - Earnings Per Share

Basic earnings per share (EPS) is computed by dividing net income attributable to Questar by the weighted-average number of common shares outstanding during the reporting period. Diluted EPS includes the potential increase in the number of outstanding shares that could result from the exercise of in-the-money stock options, the vesting of restricted stock units and performance shares that are part of the Company's Long-Term Stock Incentive Plan (LTSIP), less shares repurchased under the treasury stock method. A reconciliation of the components of basic and diluted shares used in the EPS calculation follows:

	3 Months Ended June 30,		6 Months Ended June 30,		12 Months Ended June 30,
	2011	2010	2011	2010	2011	2010
	(in millions)
Weighted-average basic common shares outstanding	177.5	175.1	177.2	175.0	177.0	174.6
Potential number of shares issuable under the Company's LTSIP	1.3	2.5	1.5	2.4	2.0	2.3
Weighted average diluted common shares outstanding	178.8	177.6	178.7	177.4	179.0	176.9