Goodwill, Customer Relationships and Other Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Jan. 31, 2019	Jan. 01, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Control premium, percent						4.10%	4.50%
Goodwill impairment	$ 0	$ 0	$ 6,500	$ 0	$ 6,506
Amortization of intangible assets	440			871	$ 869
Intangible assets, gross (including goodwill)	$ 44,000			$ 44,000

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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