Leases - NPC - Schedule of Lease Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Variable	$ 439	$ 552	$ 611
Operating	136	136	161
Finance lease, amortization	21	20	23
Finance lease, interest expense	35	36	38
Total lease costs	$ 677	$ 788	$ 848
Weighted-average remaining lease term (years):
Operating leases	7 years 4 months 24 days	7 years 4 months 24 days	7 years 7 months 6 days
Finance leases	27 years 6 months	28 years 1 month 6 days	28 years 1 month 6 days
Weighted-average discount rate:
Operating leases	4.50%	4.10%	4.30%
Finance leases	8.60%	8.60%	8.60%
NPC
Lessee, Lease, Description [Line Items]
Variable	$ 264	$ 369	$ 449
Operating	2	2	2
Finance lease, amortization	15	14	13
Finance lease, interest expense	26	27	28
Total lease costs	$ 307	$ 412	$ 492
Weighted-average remaining lease term (years):
Operating leases	3 years 8 months 12 days	4 years 9 months 18 days	5 years 8 months 12 days
Finance leases	28 years 2 months 12 days	29 years 1 month 6 days	28 years 8 months 12 days
Weighted-average discount rate:
Operating leases	4.50%	4.50%	4.50%
Finance leases	8.60%	8.60%	8.60%