XML 78 R68.htm IDEA: XBRL DOCUMENT v3.21.1
Fair Value Measurements - Narrative (Details) - USD ($)
$ in Millions
Mar. 31, 2021
Dec. 31, 2020
Mar. 31, 2020
Fair Value Disclosures [Abstract]      
Estimated fair value of long-term debt $ 3,050 $ 3,110 $ 2,770
Carrying value of long-term debt $ 2,880 $ 2,900 $ 2,900