Stock Compensation Plans	3 Months Ended
Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Compensation Plans	NOTE 13. STOCK COMPENSATION PLANS Our Board of Directors granted 4.2 million stock options, 0.3 million restricted stock units and 0.2 million performance share units during the three months ended March 31, 2020 under our stock compensation plans. The weighted average exercise price per share and weighted average fair value per share of the stock option grants during the three months ended March 31, 2020 were $10.12 and $1.97, respectively. We estimated the fair value of the stock options using the following assumptions in our Black-Scholes model: Expected term: 7.5 years Interest rate: 1.29% Volatility: 41.28% Dividend yield: 6.54% We measure the fair value of grants of restricted stock units and performance share units based primarily on the closing market price of a share of our common stock on the date of the grant, modified as appropriate to take into account the features of such grants. The weighted average fair value per share was $10.12 for restricted stock units and $7.80 for performance share units granted during the three months ended March 31, 2020. We recognized stock-based compensation expense of $6 million and $3 million during the three months ended March 31, 2020 and 2019, respectively. At March 31, 2020, unearned compensation cost related to the unvested portion of all stock-based awards was approximately $39 million and is expected to be recognized over the remaining vesting period of the respective grants, through the first quarter of 2024.

Stock Compensation Plans

3 Months Ended

Mar. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

NOTE 13. STOCK COMPENSATION PLANS

Our Board of Directors granted 4.2 million stock options, 0.3 million restricted stock units and 0.2 million performance share units during the three months ended March 31, 2020 under our stock compensation plans. The weighted average exercise price per share and weighted average fair value per share of the stock option grants during the three months ended March 31, 2020 were $10.12 and $1.97, respectively. We estimated the fair value of the stock options using the following assumptions in our Black-Scholes model:

Expected term: 7.5 years

Interest rate: 1.29%

Volatility: 41.28%

Dividend yield: 6.54%

We measure the fair value of grants of restricted stock units and performance share units based primarily on the closing market price of a share of our common stock on the date of the grant, modified as appropriate to take into account the features of such grants. The weighted average fair value per share was $10.12 for restricted stock units and $7.80 for performance share units granted during the three months ended March 31, 2020.

We recognized stock-based compensation expense of $6 million and $3 million during the three months ended March 31, 2020 and 2019, respectively. At March 31, 2020, unearned compensation cost related to the unvested portion of all stock-based awards was approximately $39 million and is expected to be recognized over the remaining vesting period of the respective grants, through the first quarter of 2024.