(Fair Value Measurements Using Significant Unobservable Inputs (Level 3)) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Mortgage backed securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, January 1	$ 133
Fair value of plan assets, December 31	126	$ 133
Mortgage backed securities \| Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, December 31	0
Other fixed income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, January 1	(1,585)
Fair value of plan assets, December 31	(1,482)	(1,585)
Derivatives
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, January 1	336
Fair value of plan assets, December 31	(21)	336
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, January 1	12,018	10,165
Fair value of plan assets, December 31	12,075	12,018
U.S. Plans \| Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, January 1	8	(5)
Relating to assets still held at the reporting date	(18)	22
Relating to assets sold during the period	(101)	267
Purchases, sales and settlements	106	(276)
Transfers in and/or out of Level 3	0	0
Fair value of plan assets, December 31	(5)	8
U.S. Plans \| Mortgage backed securities \| Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, January 1	0
Fair value of plan assets, December 31		0
U.S. Plans \| Other fixed income \| Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, January 1	14	14
Relating to assets still held at the reporting date	2	1
Relating to assets sold during the period	0	(1)
Purchases, sales and settlements	0	0
Transfers in and/or out of Level 3	0	0
Fair value of plan assets, December 31	16	14
U.S. Plans \| Derivatives \| Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, January 1	(6)	(19)
Relating to assets still held at the reporting date	(20)	21
Relating to assets sold during the period	(101)	268
Purchases, sales and settlements	106	(276)
Transfers in and/or out of Level 3	0	0
Fair value of plan assets, December 31	$ (21)	$ (6)

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets sold.

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets still held.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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- Definition

Amount, measured using unobservable input, of increase (decrease) in plan asset of defined benefit plan from purchase, sale and settlement of trade associated with underlying investment.

+ References

+ Details

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan, for assets transferred into (out of) Level 3 of fair value hierarchy. Includes, but is not limited to, transfer due to change in observability of significant inputs.

+ References

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