Employee Benefit Plans - Schedule of Allocation of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 2,422	$ 2,327
Percent of total assets	100.00%	100.00%
Growth-Oriented
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 1,271	$ 1,434
Percent of total assets	52.00%	62.00%
Equity
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 1,142	$ 1,249
Percent of total assets	47.00%	54.00%
Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 114	$ 144
Percent of total assets	4.00%	6.00%
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 15	$ 41
Percent of total assets	1.00%	2.00%
Immunizing
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 1,151	$ 893
Percent of total assets	48.00%	38.00%
Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 911	$ 777
Percent of total assets	38.00%	33.00%
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 240	$ 116
Percent of total assets	10.00%	5.00%