Goodwill and Other Intangible Assets (Details) - Other Intangible Assets - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Jan. 02, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount			$ 407	$ 304
Intangible assets subject to amortization, accumulated amortization			273	253
Intangible assets subject to amortization, net			134	51
Intangible assets not subject to amortization			226	226
Total other intangible assets, gross carrying amount			633	530
Total other intangible assets, net			360	277
Amortization expense of intangible assets			21	12	$ 13
Estimated intangible asset amortization expense, 2025			21
Estimated intangible asset amortization expense, 2026			20
Estimated intangible asset amortization expense, 2027			17
Estimated intangible asset amortization expense, 2028			9
Estimated intangible asset amortization expense, 2029			9
Corvus [Member]
Other intangible assets by major asset class
Intangible assets recorded in connection with acquisition of Corvus	$ 105
Weighted average amortization period of intangible assets recorded in connection with acquisition of Corvus (in years)	13 years
Customer-related [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount			185	100
Intangible assets subject to amortization, accumulated amortization			74	59
Intangible assets subject to amortization, net			111	41
Customer-related [Member] | Corvus [Member]
Other intangible assets by major asset class
Intangible assets recorded in connection with acquisition of Corvus	$ 87	$ 87
Weighted average amortization period of intangible assets recorded in connection with acquisition of Corvus (in years)	14 years
Contract-based [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount			204	204
Intangible assets subject to amortization, accumulated amortization			196	194
Intangible assets subject to amortization, net			8	$ 10
Insurance Contracts Acquired in Business Combination [Member]
Other intangible assets by major asset class
Estimated intangible asset amortization expense, 2025			2
Estimated intangible asset amortization expense, 2026			1
Estimated intangible asset amortization expense, 2027			1
Estimated intangible asset amortization expense, 2028			1
Estimated intangible asset amortization expense, 2029			1
Marketing-related [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount			18
Intangible assets subject to amortization, accumulated amortization			3
Intangible assets subject to amortization, net			$ 15
Marketing-related [Member] | Corvus [Member]
Other intangible assets by major asset class
Intangible assets recorded in connection with acquisition of Corvus	$ 18	$ 18
Weighted average amortization period of intangible assets recorded in connection with acquisition of Corvus (in years)	7 years