Discontinued Operations - Narrative (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 01, 2018 subsidiary
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss Contingency, Estimate of Possible Loss	$ 77
VIAC And DSL | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Subsidiaries to be discontinued | subsidiary		2
Pro Forma | VIAC And DSL | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amount of Adjustment to Prior Period Gain (Loss) on Disposal, Net of Tax	$ (82)