Supplemental Income Statement Information (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended
Mar. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Interest expense		$ 121		$ 137	$ 253	$ 260
Interest income		(8)		(9)	(12)	(19)
Pension and postretirement net periodic benefit cost (benefit)		(80)		(38)	(159)	(76)
Total		$ 33		$ 90	$ 82	$ 165
Fixed rate medium term note due 2022
Loss on extinguishment of debt	$ 11		$ 11

Amount of net periodic benefit cost (credit) for defined benefit plan.

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