Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Schedule of Fair Value Measurements

The following table presents the fair value of our variable rate term debt and senior notes, estimated using inputs based on bid and offer prices that are Level 2 inputs, and principal carrying amount (in millions):

	As of December 31,
	2020		2019
Fair value of our variable term debt and senior notes	$	12,477	$	12,075
Principal carrying amount of our variable term debt and senior notes	12,453		11,900