Benefit Plans - Pension and postretirement benefits remeasurement gains and losses (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Retirement Benefits [Abstract]
Discount rate	$ (73)	$ (420)	$ 51	$ (1,005)
Other assumptions	3	(20)	6	(211)
Remeasurement of plan assets (gains) losses	30	699	(150)	1,228
Remeasurement (gains) losses	$ (40)	$ 259	$ (93)	$ 12

Amount of gain (loss), recognized immediately as component of net periodic benefit (cost) credit, for change in value of benefit obligation or plan assets from experience different from that assumed, change in actuarial assumption, or consequence of temporarily deviating from substantive plan. Includes, but is not limited to, amount in excess of 10 percent of greater of fair value of plan assets or benefit obligation.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 3A
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480535/715-20-45-3A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (h)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-6

Name:	us-gaap_DefinedBenefitPlanActuarialGainLossImmediateRecognitionAsComponentInNetPeriodicBenefitCostCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration