Goodwill and Other Intangible Assets - Changes in Goodwill and Other Intangible Assets (Details) $ in Millions	6 Months Ended
Jun. 30, 2019 USD ($)
Goodwill and Other Intangible Assets [Roll Forward]
Amortizing Intangible Assets, Beginning Balance	$ 342
Amortizing Intangible Assets, Amortization expense	36
Impairment of Intangible Assets (Excluding Goodwill)	0
Impairment of Intangible Assets, Finite-lived	0
Amortizing Intangible Assets, Ending Balance	305
Goodwill, Beginning Balance	4,044
Goodwill, Impairment Loss	0
Goodwill, Ending Balance	4,039
Other Non-Amortizing Intangible Assets, Beginning Balance	2,635
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	50
Other Non-Amortizing Intangible Assets, Ending Balance	2,575
Finite-Lived Intangible Assets [Member]
Goodwill and Other Intangible Assets [Roll Forward]
Increase (Decrease) in Assets Held-for-sale	(1)
Goodwill [Member]
Goodwill and Other Intangible Assets [Roll Forward]
Increase (Decrease) in Assets Held-for-sale	(5)
Indefinite-lived Intangible Assets [Member]
Goodwill and Other Intangible Assets [Roll Forward]
Increase (Decrease) in Assets Held-for-sale	$ (10)

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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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value.

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The increase (decrease) during the period in book value of long-lived assets that the reporting entity plans to sell within one year (or one business cycle).

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Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

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