The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Intangible assets, net	$ 17	$ 102
Amortization of intangibles	20	23	$ 37
Amortization, 2020	7
Amortization, 2021	6
Amortization, 2022	$ 4
Customer Contracts
Goodwill [Line Items]
Intangible assets, net		31
Technology-Based Intangible Assets
Goodwill [Line Items]
Intangible assets, net		$ 71