Goodwill, Customer Relationships and Other Intangible Assets - Rollforward Goodwill (Details) - USD ($)		3 Months Ended		12 Months Ended
	Oct. 31, 2023	Dec. 31, 2024	Jun. 30, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill Activity
As of beginning of period				$ 1,964,000,000	$ 12,657,000,000
Impairment	$ (1,900,000,000)	$ 0	$ (8,800,000,000)	0	(10,693,000,000)	$ (3,271,000,000)
As of end of period		1,964,000,000		1,964,000,000	1,964,000,000	12,657,000,000
Goodwill accumulated impairment loss		21,700,000,000		21,700,000,000	21,700,000,000	11,000,000,000.0
Business
Goodwill Activity
As of beginning of period				0	7,906,000,000
Impairment					(7,906,000,000)
As of end of period		0		0	0	7,906,000,000
Mass Markets
Goodwill Activity
As of beginning of period				1,964,000,000	4,751,000,000
Impairment					(2,787,000,000)
As of end of period		$ 1,964,000,000		$ 1,964,000,000	$ 1,964,000,000	$ 4,751,000,000