Benefit Plans (Fair Value of Plan Assets) (Details) - USD ($)		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		$ 1,249,000,000	$ 1,154,000,000	$ 1,026,000,000
UNITED STATES | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		4,000,000	4,000,000
UNITED STATES | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		1,245,000,000	1,150,000,000
UNITED STATES | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
UNITED STATES | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		547,000,000	372,000,000
UNITED STATES | Mutual funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
UNITED STATES | Mutual funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		547,000,000	372,000,000
UNITED STATES | Mutual funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
UNITED STATES | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	[1]	698,000,000	775,000,000
UNITED STATES | Mutual funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
UNITED STATES | Mutual funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		698,000,000	775,000,000
UNITED STATES | Mutual funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
UNITED STATES | Real estate
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	3,000,000
UNITED STATES | Real estate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
UNITED STATES | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	3,000,000
UNITED STATES | Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
UNITED STATES | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		4,000,000	4,000,000
UNITED STATES | Cash and Cash Equivalents [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		4,000,000	4,000,000
UNITED STATES | Cash and Cash Equivalents [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
UNITED STATES | Cash and Cash Equivalents [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		112,000,000	129,000,000	$ 410,000,000
Foreign Plan [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		35,000,000	37,000,000
Foreign Plan [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		74,000,000	88,000,000
Foreign Plan [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		3,000,000	4,000,000
Foreign Plan [Member] | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		16,000,000	19,000,000
Foreign Plan [Member] | Mutual funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		16,000,000	19,000,000
Foreign Plan [Member] | Mutual funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Mutual funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Private equity
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		1,000,000	1,000,000
Foreign Plan [Member] | Private equity | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Private equity | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Private equity | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		1,000,000	1,000,000
Foreign Plan [Member] | Government debt securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Government debt securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Government debt securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Government debt securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	[2]	92,000,000	105,000,000
Foreign Plan [Member] | Mutual funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		18,000,000	17,000,000
Foreign Plan [Member] | Mutual funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		74,000,000	88,000,000
Foreign Plan [Member] | Mutual funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Real estate
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		1,000,000	2,000,000
Foreign Plan [Member] | Real estate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		1,000,000	2,000,000
Foreign Plan [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Cash and Cash Equivalents [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Cash and Cash Equivalents [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Cash and Cash Equivalents [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Other assets
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		2,000,000	2,000,000
Foreign Plan [Member] | Other assets | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		1,000,000	1,000,000
Foreign Plan [Member] | Other assets | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0	0
Foreign Plan [Member] | Other assets | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		$ 1,000,000	$ 1,000,000

[1] Mutual funds categorized as debt securities consist of mutual funds for which debt securities are the primary underlying investment

[2] Mutual funds categorized as debt securities consist of mutual funds for which debt securities are the primary underlying investment