Debt (Summary of Outstanding Debt) (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2019 EUR (€)	Oct. 31, 2019 EUR (€)	Dec. 31, 2018 EUR (€)
Principal outstanding
Short-term debt	$ 75,000,000	$ 89,000,000
Total long-term debt	7,944,000,000	8,667,000,000
Less: current maturities	(62,000,000)	(81,000,000)
Total long-term debt, less current maturities	7,882,000,000	8,586,000,000
Carrying amount
Short-term debt	75,000,000	89,000,000
Total long-term debt	7,880,000,000	8,574,000,000
Less: current maturities	(62,000,000)	(81,000,000)
Total long-term debt, less current maturities	7,818,000,000	8,493,000,000
Term loan facilities | U.S. dollar at LIBOR plus 1.5% due 2024
Principal outstanding
Total long-term debt	1,100,000,000
Carrying amount
Total long-term debt	1,094,000,000
Debt instrument, face amount	$ 1,100,000,000
Term loan facilities | U.S. dollar at LIBOR plus 1.5% due 2024 | LIBOR
Carrying amount
Basis spread on variable rate (as a percent)	1.50%
Term loan facilities | US Dollar at LIBOR Plus One Point Seven Five Percentage Due Two Thousand Twenty Two [Member]
Principal outstanding
Total long-term debt		815,000,000
Carrying amount
Total long-term debt		810,000,000
Term loan facilities | U.S. dollar at LIBOR plus 2.00% due 2025
Principal outstanding
Total long-term debt	$ 0	887,000,000
Carrying amount
Total long-term debt	0	$ 864,000,000
Term loan facilities | U.S. dollar at LIBOR plus 2.00% due 2025 | LIBOR
Carrying amount
Basis spread on variable rate (as a percent)		2.00%
Term loan facilities | Euro at EURIBOR Plus One Point Five Percentage Due Two Thousand and Twenty Four [Member]
Principal outstanding
Total long-term debt	505,000,000
Carrying amount
Total long-term debt	504,000,000
Debt instrument, face amount	$ 505,000,000		€ 450,000,000
Term loan facilities | Euro at EURIBOR Plus One Point Five Percentage Due Two Thousand and Twenty Four [Member] | EURIBOR
Carrying amount
Basis spread on variable rate (as a percent)	1.50%
Term loan facilities | Euro at EURIBOR Plus One Point Seven Five Percentage Due Two Thousand and Twenty Two [Member] [Domain]
Principal outstanding
Total long-term debt		$ 301,000,000
Carrying amount
Total long-term debt		301,000,000
Debt instrument, face amount | €			€ 450,000,000		€ 263,000,000
Term loan facilities | Euro at EURIBOR plus 2.375% due 2025
Principal outstanding
Total long-term debt	$ 0	855,000,000			€ 746,000,000
Carrying amount
Total long-term debt	0	$ 846,000,000
Term loan facilities | Euro at EURIBOR plus 2.375% due 2025 | EURIBOR
Carrying amount
Basis spread on variable rate (as a percent)		2.375%
Senior notes and debentures: | €650 at 4.0% due 2022
Principal outstanding
Total long-term debt	729,000,000	$ 745,000,000
Carrying amount
Total long-term debt	$ 725,000,000	740,000,000
Debt instrument stated percentage	4.00%		4.00%
Debt instrument, face amount | €			€ 650,000,000
Senior notes and debentures: | U. S. dollar at 4.50% due 2023
Principal outstanding
Total long-term debt	$ 1,000,000,000	1,000,000,000
Carrying amount
Total long-term debt	$ 995,000,000	993,000,000
Debt instrument stated percentage	4.50%		4.50%
Senior notes and debentures: | €335 at 2.25% due 2023
Principal outstanding
Total long-term debt	$ 376,000,000	384,000,000
Carrying amount
Total long-term debt	$ 372,000,000	380,000,000
Debt instrument stated percentage	2.25%		2.25%
Debt instrument, face amount | €			€ 335,000,000
Senior notes and debentures: | Euro .75% due 2023 [Member]
Principal outstanding
Total long-term debt	$ 617,000,000	0
Carrying amount
Total long-term debt	$ 610,000,000	0
Debt instrument stated percentage	0.75%		0.75%	0.75%
Debt instrument, face amount	$ 617,000,000		€ 550,000,000	€ 550,000,000
Senior notes and debentures: | €600 at 2.625% due 2024
Principal outstanding
Total long-term debt	673,000,000	688,000,000
Carrying amount
Total long-term debt	$ 668,000,000	682,000,000
Debt instrument stated percentage	2.625%		2.625%
Debt instrument, face amount | €			€ 600,000,000
Senior notes and debentures: | €600 at 3.375% due 2025
Principal outstanding
Total long-term debt	$ 673,000,000	688,000,000
Carrying amount
Total long-term debt	$ 667,000,000	681,000,000
Debt instrument stated percentage	3.375%		3.375%
Debt instrument, face amount | €			€ 600,000,000
Senior notes and debentures: | U.S. dollar at 4.25% due 2026
Principal outstanding
Total long-term debt	$ 400,000,000	400,000,000
Carrying amount
Total long-term debt	$ 395,000,000	394,000,000
Debt instrument stated percentage	4.25%		4.25%
Senior notes and debentures: | U.S. dollar at 4.75% due 2026
Principal outstanding
Total long-term debt	$ 875,000,000	875,000,000
Carrying amount
Total long-term debt	$ 863,000,000	863,000,000
Debt instrument stated percentage	4.75%		4.75%
Senior notes and debentures: | U.S. dollar at 7.375% due 2026
Principal outstanding
Total long-term debt	$ 350,000,000	350,000,000
Carrying amount
Total long-term debt	$ 348,000,000	348,000,000
Debt instrument stated percentage	7.375%		7.375%
Senior notes and debentures: | €500 at 2.875% due 2026
Principal outstanding
Total long-term debt	$ 561,000,000	573,000,000
Carrying amount
Total long-term debt	$ 554,000,000	566,000,000
Debt instrument stated percentage	2.875%		2.875%
Debt instrument, face amount | €			€ 500,000,000
Senior notes and debentures: | U.S. dollar at 7.50% due 2096
Principal outstanding
Total long-term debt	$ 40,000,000	40,000,000
Carrying amount
Total long-term debt	$ 40,000,000	40,000,000
Debt instrument stated percentage	7.50%		7.50%
Other indebtedness, fixed rate
Principal outstanding
Total long-term debt	$ 39,000,000	62,000,000
Carrying amount
Total long-term debt	$ 39,000,000	62,000,000
Other indebtedness, fixed rate | Minimum
Carrying amount
Debt instrument stated percentage	4.00%		4.00%
Other indebtedness, fixed rate | Maximum
Carrying amount
Debt instrument stated percentage	7.50%		7.50%
Other indebtedness, variable rate
Principal outstanding
Total long-term debt	$ 6,000,000	4,000,000
Carrying amount
Total long-term debt	$ 6,000,000	$ 4,000,000
Average variable rates	2.60%		2.60%
Debt Instrument Interest Rate Variable Percentage Rate Range Maximum	4.30%