Stock Compensation Plans	9 Months Ended
Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock Compensation Plans	NOTE 12. STOCK COMPENSATION PLANS Our Board of Directors granted 0.9 million performance share units and 0.7 million restricted stock units during the nine months ended September 30, 2021 under our stock compensation plans. We measure the fair value of grants of performance share units and restricted stock 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 $19.32 for performance share units and $16.22 for restricted stock units granted during the nine months ended September 30, 2021. We recognized stock-based compensation expense of $11 million and $22 million during the three and nine months ended September 30, 2021, respectively. At September 30, 2021, unearned compensation cost related to the unvested portion of all stock-based awards was approximately $61 million and is expected to be recognized over the remaining vesting period of the respective grants, through the third quarter of 2024. We recognized stock-based compensation expense of $9 million and $23 million during the three and nine months ended September 30, 2020, respectively.

Stock Compensation Plans

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

NOTE 12. STOCK COMPENSATION PLANS

Our Board of Directors granted 0.9 million performance share units and 0.7 million restricted stock units during the nine months ended September 30, 2021 under our stock compensation plans. We measure the fair value of grants of performance share units and restricted stock 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 $19.32 for performance share units and $16.22 for restricted stock units granted during the nine months ended September 30, 2021.

We recognized stock-based compensation expense of $11 million and $22 million during the three and nine months ended September 30, 2021, respectively. At September 30, 2021, unearned compensation cost related to the unvested portion of all stock-based awards was approximately $61 million and is expected to be recognized over the remaining vesting period of the respective grants, through the third quarter of 2024. We recognized stock-based compensation expense of $9 million and $23 million during the three and nine months ended September 30, 2020, respectively.