Leases - NPC - Schedule of Operating and Finance Lease (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Right-of-use assets:
Operating leases	$ 501	$ 545
Operating lease right-of-use asset, statement of financial position	Other assets	Other assets
Finance leases	$ 399	$ 418
Finance lease right-of-use asset, statement of financial position	Other assets	Other assets
Total right-of-use assets	$ 900	$ 963
Lease liabilities:
Operating leases	$ 555	$ 605
Operating lease liability, statement of financial position	Other current liabilities, Other long-term liabilities	Other current liabilities, Other long-term liabilities
Finance leases	$ 413	$ 432
Finance lease liability, statement of financial position	Other current liabilities, Other long-term liabilities	Other current liabilities, Other long-term liabilities
Total lease liabilities	$ 968	$ 1,037
NPC
Right-of-use assets:
Operating leases	$ 7	$ 9
Operating lease right-of-use asset, statement of financial position	Other assets	Other assets
Finance leases	$ 289	$ 303
Finance lease right-of-use asset, statement of financial position	Other assets	Other assets
Total right-of-use assets	$ 296	$ 312
Lease liabilities:
Operating leases	$ 9	$ 11
Operating lease liability, statement of financial position	Other current liabilities, Other long-term liabilities	Other current liabilities, Other long-term liabilities
Finance leases	$ 298	$ 313
Finance lease liability, statement of financial position	Other current liabilities, Other long-term liabilities	Other current liabilities, Other long-term liabilities
Total lease liabilities	$ 307	$ 324