Employee Benefits - Fair Value of Plan Assets (Details) - Combined Pension Plan - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 4,201	$ 4,476	$ 4,715	$ 8,531
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6	5	5
Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,359	2,192
Total investments, excluding investments valued at NAV | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,183	2,660
Total investments, excluding investments valued at NAV | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	722	728
Total investments, excluding investments valued at NAV | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,455	1,927
Total investments, excluding investments valued at NAV | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6	5
Investment grade bonds | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,763	2,228
Investment grade bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	372	390
Investment grade bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,391	1,838
Investment grade bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Investment grade bonds | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	72	105
High yield bonds | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	30	36
High yield bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
High yield bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26	32
High yield bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	4	4
High yield bonds | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	340	110
Emerging market bonds | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	104	114
Emerging market bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	70	57
Emerging market bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34	57
Emerging market bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Emerging market bonds | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	69	0
U.S. stocks | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	263	248
U.S. stocks | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	260	247
U.S. stocks | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2	0
U.S. stocks | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	1	1
U.S. stocks | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6	51
Non-U.S. stocks | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15	6
Non-U.S. stocks | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14	6
Non-U.S. stocks | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. stocks | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	0	$ 0
Non-U.S. stocks | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	529	412
Cash equivalents and short-term investments | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8
Cash equivalents and short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6
Cash equivalents and short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2
Cash equivalents and short-term investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Cash equivalents and short-term investments | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	277	318
Multi-asset strategies | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		28
Multi-asset strategies | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		28
Multi-asset strategies | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Multi-asset strategies | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Multi-asset strategies | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	27
Other receivables | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27
Repurchase agreements & other obligations | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(361)	(375)
Repurchase agreements & other obligations | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Repurchase agreements & other obligations | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(361)	(375)
Repurchase agreements & other obligations | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivatives | Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(7)	(1)
Derivatives | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(1)	(1)
Derivatives | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(6)	0
Derivatives | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Emerging market stocks | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	10
Private equity | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	253	272
Private debt | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	398	421
Market neutral hedge funds | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	85	77
Directional hedge funds | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	108	124
Real estate | Investments valued at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 218	$ 265