XML 38 R27.htm IDEA: XBRL DOCUMENT v3.21.1
Fair Values of Financial Instruments (Tables)
3 Months Ended
Mar. 31, 2021
Fair Value Disclosures [Abstract]  
Schedule of Carrying Amounts and Estimated Fair Values The carrying amounts and estimated fair values, based on Level 1 inputs, of long-term debt consist of the following:
 March 31, 2021December 31, 2020
Carrying
Amount
Fair
Value
Carrying
Amount
Fair
Value
 ($ in millions)
Long-term debt, including current maturities$(12,617)$(15,249)$(12,681)$(16,664)