Earnings Per Common Share (Tables)

3 Months Ended

Mar. 31, 2017

Earnings Per Share [Abstract]

Schedule of reconciliations of the numerators and denominators used in the computations of basic and diluted earnings per common share

Reconciliations of the numerators and denominators used in the computations of basic and diluted earnings per common share were as follows, in millions: 

	Three Months Ended March 31,
	2017		2016
Numerator (basic and diluted):
Net income	$	140	$	109
Less: Allocation to unvested restricted stock awards	1		1
Net income available to common shareholders	$	139	$	108
Denominator:
Basic common shares (based upon weighted average)	317		330
Add: Stock option dilution	4		3
Diluted common shares	321		333