Fair Value Measurements - Gains (Loss) and Interest Expense on Interest Rate Swap Contracts (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recorded in accumulated other comprehensive loss, net of tax	$ 0	$ (3)
Interest rate swap
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recorded in accumulated other comprehensive loss, net of tax	5	(16)
Interest expense recorded related to interest rate swap contracts	$ 5	$ 2

Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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