XML 39 R26.htm IDEA: XBRL DOCUMENT v3.21.1
Fair Value Measurements (Tables)
3 Months Ended
Mar. 31, 2021
Fair Value Disclosures [Abstract]  
Fair value of financial instruments The estimated fair values of our other financial instruments, all of which are categorized in Level 1 of the fair value hierarchy, as of March 31, 2021 and December 31, 2020 have been calculated based upon available market information, and were as follows: 
 March 31, 2021December 31, 2020
 Carrying
Amount
Fair
Value
Carrying
Amount
Fair
Value
Senior notes$6,967 $7,344 $6,965 $7,470