Per Share Data	3 Months Ended
Jun. 30, 2018
Earnings Per Share [Abstract]
Per Share Data	Per Share Data Basic net income per common share is calculated by dividing net income by the weighted average number of common shares outstanding during the period. Diluted net income per common share adjusts basic net income per common share, computed using the treasury stock method, for the effects of potentially dilutive common shares, if the effect is not antidilutive. As of the three-month period ended June 30, 2018, the computation of diluted net income per common share includes the effect of dilutive securities consisting of approximately 47 million options and restricted stock units and 4 million shares attributable to warrants, of which 2 million related to the warrant held by SoftBank. As of the three-month period ended June 30, 2018, outstanding options to purchase shares totaling 9 million were not included in the computation of diluted net income per common share because to do so would have been antidilutive. As of the three-month period ended June 30, 2017, outstanding options to purchase shares totaling 4 million were not included in the computation of diluted net income per common share because to do so would have been antidilutive. The computation of diluted net income per common share as of the three-month period ended June 30, 2017 includes the effect of dilutive securities consisting of approximately 59 million options and restricted stock units, in addition to 24 million shares attributable to warrants, of which 20 million relate to shares issuable under the warrant held by SoftBank. At the close of the merger with SoftBank, the warrant was issued at $5.25 per share. On July 10, 2018, SoftBank exercised its warrant in full to purchase 55 million shares of stock for $287 million.

Per Share Data

Basic net income per common share is calculated by dividing net income by the weighted average number of common shares outstanding during the period. Diluted net income per common share adjusts basic net income per common share, computed using the treasury stock method, for the effects of potentially dilutive common shares, if the effect is not antidilutive. As of the three-month period ended June 30, 2018, the computation of diluted net income per common share includes the effect of dilutive securities consisting of approximately 47 million options and restricted stock units and 4 million shares attributable to warrants, of which 2 million related to the warrant held by SoftBank. As of the three-month period ended June 30, 2018, outstanding options to purchase shares totaling 9 million were not included in the computation of diluted net income per common share because to do so would have been antidilutive. As of the three-month period ended June 30, 2017, outstanding options to purchase shares totaling 4 million were not included in the computation of diluted net income per common share because to do so would have been antidilutive. The computation of diluted net income per common share as of the three-month period ended June 30, 2017 includes the effect of dilutive securities consisting of approximately 59 million options and restricted stock units, in addition to 24 million shares attributable to warrants, of which 20 million relate to shares issuable under the warrant held by SoftBank. At the close of the merger with SoftBank, the warrant was issued at $5.25 per share. On July 10, 2018, SoftBank exercised its warrant in full to purchase 55 million shares of stock for $287 million.