Postretirement Benefit Plans (Fair Value of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure
Fair value of plan assets	$ 679	$ 691
Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	50	43
Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	185	188
Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	368	384	$ 13
NAV Practical Expedient
Defined Benefit Plan Disclosure
Fair value of plan assets	76	76
Global stock funds/securities
Defined Benefit Plan Disclosure
Fair value of plan assets	128	118
Global stock funds/securities | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	43	38
Global stock funds/securities | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	71	66
Global stock funds/securities | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Global stock funds/securities | NAV Practical Expedient
Defined Benefit Plan Disclosure
Fair value of plan assets	14	14
Diversified growth and income funds
Defined Benefit Plan Disclosure
Fair value of plan assets	28	26
Diversified growth and income funds | NAV Practical Expedient
Defined Benefit Plan Disclosure
Fair value of plan assets	28	26
Corporate bonds
Defined Benefit Plan Disclosure
Fair value of plan assets	100	105
Corporate bonds | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	1	1
Corporate bonds | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	92	97
Corporate bonds | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Corporate bonds | NAV Practical Expedient
Defined Benefit Plan Disclosure
Fair value of plan assets	7	7
Government bonds
Defined Benefit Plan Disclosure
Fair value of plan assets	44	47
Government bonds | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Government bonds | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	17	19
Government bonds | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Government bonds | NAV Practical Expedient
Defined Benefit Plan Disclosure
Fair value of plan assets	27	28
Hedging instruments
Defined Benefit Plan Disclosure
Fair value of plan assets	5	6
Hedging instruments | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Hedging instruments | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	5	6
Hedging instruments | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Hedge funds
Defined Benefit Plan Disclosure
Fair value of plan assets	0	1
Hedge funds | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Hedge funds | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Hedge funds | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Hedge funds | NAV Practical Expedient
Defined Benefit Plan Disclosure
Fair value of plan assets		1
Insurance contracts and other
Defined Benefit Plan Disclosure
Fair value of plan assets	368	384
Insurance contracts and other | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Insurance contracts and other | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Insurance contracts and other | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	368	384
Cash and cash equivalents
Defined Benefit Plan Disclosure
Fair value of plan assets	6	4
Cash and cash equivalents | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	6	4
Cash and cash equivalents | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Cash and cash equivalents | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	$ 0	$ 0