Note 12 - Pension and Postretirement Benefit Plans - Fair Value of Pension Plan Assets (Details) - Pension Plan [Member] - USD ($) $ in Millions		Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Fair value of plan assets		$ 850		$ 802
UNITED STATES
Fair value of plan assets		781		724		$ 1,301
UNITED STATES | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets		40		39
UNITED STATES | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		247		288
UNITED STATES | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets		6		4
UNITED STATES | Fair Value Measured at Net Asset Value Per Share [Member]
Fair value of plan assets	[1]	488		393
Foreign Plan [Member]
Fair value of plan assets		69		78		71
Foreign Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets		0		0
Foreign Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		17		32
Foreign Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets		52		46
Defined Benefit Plan, Equity Securities, US [Member]
Fair value of plan assets	[2]	40		39
Defined Benefit Plan, Equity Securities, US [Member] | UNITED STATES | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets	[2]	40		39
Defined Benefit Plan, Equity Securities, US [Member] | UNITED STATES | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	[2]			0
Defined Benefit Plan, Equity Securities, US [Member] | UNITED STATES | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets	[2]			0
Defined Benefit Plan, Equity Securities, US [Member] | UNITED STATES | Fair Value Measured at Net Asset Value Per Share [Member]
Fair value of plan assets	[1],[2]			0
Defined Benefit Plan, Equity Securities, US [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets	[2]			0
Defined Benefit Plan, Equity Securities, US [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	[2]			0
Defined Benefit Plan, Equity Securities, US [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets	[2]			0
Defined Benefit Plan, Equity Securities, US, Large Cap [Member]
Fair value of plan assets		36		28
Defined Benefit Plan, Equity Securities, US, Large Cap [Member] | UNITED STATES | Fair Value Measured at Net Asset Value Per Share [Member]
Fair value of plan assets	[1]	36		28
Defined Benefit Plan, Equity Securities, Non-US [Member]
Fair value of plan assets		23		19
Defined Benefit Plan, Equity Securities, Non-US [Member] | UNITED STATES | Fair Value Measured at Net Asset Value Per Share [Member]
Fair value of plan assets	[1]	23		19
Defined Benefit Plan, Equity Securities, Emerging Markets [Member]
Fair value of plan assets		16		9
Defined Benefit Plan, Equity Securities, Emerging Markets [Member] | UNITED STATES | Fair Value Measured at Net Asset Value Per Share [Member]
Fair value of plan assets	[1]	16		9
Corporate Debt Securities [Member]
Fair value of plan assets		572		492
Corporate Debt Securities [Member] | UNITED STATES | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		189		186
Corporate Debt Securities [Member] | UNITED STATES | Fair Value Measured at Net Asset Value Per Share [Member]
Fair value of plan assets	[1]	383		306
US Treasury Securities [Member]
Fair value of plan assets		22		37
US Treasury Securities [Member] | UNITED STATES | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		22		37
Debt Security, Government, Non-US [Member]
Fair value of plan assets		16		21
Debt Security, Government, Non-US [Member] | UNITED STATES | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		1
Debt Security, Government, Non-US [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		15		21
Defined Benefit Plan, Fixed Income Securities, Emerging Markets [Member]
Fair value of plan assets		12		11
Defined Benefit Plan, Fixed Income Securities, Emerging Markets [Member] | UNITED STATES | Fair Value Measured at Net Asset Value Per Share [Member]
Fair value of plan assets	[1]	12		11
Insurance Contracts [Member]
Fair value of plan assets	[3]	58		50
Insurance Contracts [Member] | UNITED STATES | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets		6	[3]	4	[3]	0
Insurance Contracts [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets		52	[3]	46	[3]	$ 35
Defined Benefit Plan, Real Estate [Member]
Fair value of plan assets		18		20
Defined Benefit Plan, Real Estate [Member] | UNITED STATES | Fair Value Measured at Net Asset Value Per Share [Member]
Fair value of plan assets	[1]	18		20
Other Securities [Member]
Fair value of plan assets		2		11
Other Securities [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		2		11
Defined Benefit Plan, Cash and Cash Equivalents [Member]
Fair value of plan assets		35		65
Defined Benefit Plan, Cash and Cash Equivalents [Member] | UNITED STATES | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		$ 35		$ 65

[1] Certain assets are measured at fair value using the net asset value (NAV) per share (or its equivalent) practical expedient and have not been classified in the fair value hierarchy.

[2] This category comprises a combination of small-, mid- and large-cap equity stocks that are allocated at the investment manager's discretion. Investments include common and preferred securities as well as equity funds that invest in these instruments.

[3] This category comprises contracts placed with insurance companies where the underlying assets are invested in fixed interest securities.