Acquisition - Consideration Transferred (Details) $ / shares in Units, shares in Millions, $ in Millions	Feb. 01, 2019 USD ($) $ / shares shares	Sep. 30, 2019 $ / shares	Dec. 31, 2018 $ / shares
Business Acquisition [Line Items]
Common stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Pandora
Business Acquisition [Line Items]
Pandora common stock outstanding at February 1, 2019 (shares)	$ 272
Exchange ratio (in shares per share)	1.44
Price per share of Holdings common stock as of February 1, 2019 (in dollars per share) | $ / shares	$ 5.83
Value of common stock issued to Pandora stockholders pursuant to the transactions	$ 2,285
Value of replacement equity awards attributable to pre-combination service	70
Consideration of common stock and replacement equity awards for pre-combination service	2,355
Sirius XM’s Pandora preferred stock investment (related party fair value instrument) canceled	524
Purchase price	2,879
Value attributed to par at $0.001 par value	$ 1
Common stock, par value (in dollars per share) | $ / shares	$ 0.001
Balance to capital in excess of par value	$ 2,354
Common Stock | Pandora
Business Acquisition [Line Items]
Common stock issued (in shares) | shares	392