Debt - Fair Value of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Jun. 30, 2019	Feb. 01, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Long-term debt, measured at fair value	$ 2,372		$ 3,861
Liberty SiriusXM Group | Sirius XM 3.125% Senior Notes due 2026
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt instrument interest rate (as a percent)	3.125%
Long-term debt, measured at fair value	$ 993
Liberty SiriusXM Group | Sirius XM 5.0% Senior Notes due 2027
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt instrument interest rate (as a percent)	5.00%
Long-term debt, measured at fair value	$ 1,551
Liberty SiriusXM Group | Sirius XM 4.0% Senior Notes Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt instrument interest rate (as a percent)	4.00%	4.00%
Long-term debt, measured at fair value	$ 2,000
Liberty SiriusXM Group | Sirius Xm 5.50% Senior Notes Due 2029
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt instrument interest rate (as a percent)	5.50%				5.50%
Long-term debt, measured at fair value	$ 1,337
Liberty SiriusXM Group | Sirius XM 4.125% Senior Notes Due 2030
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt instrument interest rate (as a percent)	4.125%			4.125%
Long-term debt, measured at fair value	$ 1,492
Liberty SiriusXM Group | Sirius XM 3.875% Senior Notes due 2031
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt instrument interest rate (as a percent)	3.875%
Long-term debt, measured at fair value	$ 1,459
Liberty SiriusXM Group | Pandora 1.75% Convertible Senior Notes due 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt instrument interest rate (as a percent)	1.75%					1.75%
Long-term debt, measured at fair value	$ 220