Net Income (Loss) Per Share

The following table reconciles the Company's net income (loss) attributable to common stockholders to basic and diluted net income (loss) attributable to common stockholders for the three months ended March 31, 2018 and 2017:



	Three Months Ended March 31,
	2018			2017
	(in millions)
Net income (loss) attributable to common stockholders	$	178		$	(42	)
Participating share-based earnings	(1		)	—
Basic and diluted net income (loss) attributable to common stockholders	$	177		$	(42	)

The following table is a reconciliation of basic weighted average shares outstanding to diluted weighted average shares outstanding for the three months ended March 31, 2018 and 2017:



	Three Months Ended March 31,
	2018	2017
	(in millions)
Basic weighted average shares outstanding	170	170
Dilution attributable to stock-based compensation awards	1	—
Diluted weighted average shares outstanding	171	170

Stock repurchase program. In February 2018, the Company's board of directors (the "Board") approved a $100 million common stock repurchase program to offset the impact of dilution associated with annual employee stock awards, of which $83 million remained available for use to purchase shares as of March 31, 2018. During the three months ended March 31, 2018, the Company purchased $17 million of common stock pursuant to the program.