Debt (Details) $ / shares in Units, € in Millions, $ in Millions		1 Months Ended			3 Months Ended	12 Months Ended
	Apr. 22, 2015 item	Dec. 31, 2017 USD ($)	Mar. 31, 2017 USD ($)	Nov. 30, 2016 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 EUR (€)	Dec. 31, 2017 USD ($) $ / shares	Sep. 30, 2017 USD ($)	Mar. 31, 2017 EUR (€)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 EUR (€)	Dec. 31, 2016 USD ($)	Nov. 30, 2016 EUR (€)
Debt Instrument
Total long-term debt										$ 5,132					$ 5,166
Less amounts due within one year										11					33
Long-term debt										5,121					5,133
Total leverage ratio	4.00%
Net proceeds, after deducting debt issuance costs						$ 1,458	$ 1,235	$ 4,538
New Agreement
Debt Instrument
Number financial maintenance covenants | item	1
Secured Credit Agreement
Debt Instrument
Unused Credit										$ 888
Accounts receivable securitization
Weighted average interest rate, short-term debt (as a percent)									3.17%	3.17%
Term Loan A
Debt Instrument
Total long-term debt										$ 1,148					1,395
Face Value										1,575
Net proceeds, after deducting debt issuance costs						$ 1,148
Term Loan A (279 million EUR at December 31, 2016)
Debt Instrument
Total long-term debt														€ 279	282
Senior Notes 6.75%, due 2020 (500 million EUR)
Debt Instrument
Total long-term debt									€ 500	$ 594					523
Interest rate, stated percentage									6.75%	6.75%
Fair values of fixed rate debt obligations
Principal Amount										$ 597
Indicated Market Price (in dollars per share) | $ / shares										$ 116.99
Fair Value										$ 699
Senior Notes 4.875%, due 2021 (330 million EUR)
Debt Instrument
Total long-term debt									€ 330	$ 392					345
Interest rate, stated percentage									4.875%	4.875%
Fair values of fixed rate debt obligations
Principal Amount										$ 394
Indicated Market Price (in dollars per share) | $ / shares										$ 113.43
Fair Value										$ 447
Senior Notes 5.00%, due 2022
Debt Instrument
Total long-term debt										$ 496					495
Interest rate, stated percentage									5.00%	5.00%
Fair values of fixed rate debt obligations
Principal Amount										$ 500
Indicated Market Price (in dollars per share) | $ / shares										$ 104.24
Fair Value										$ 521
Senior Notes 5.875%, due 2023
Debt Instrument
Total long-term debt										$ 685					682
Interest rate, stated percentage									5.875%	5.875%
Fair values of fixed rate debt obligations
Principal Amount										$ 700
Indicated Market Price (in dollars per share) | $ / shares										$ 108.15
Fair Value										$ 757
Senior Notes 3.125%, due 2024 (725 million EUR at December 31,2017 and 500 million EUR at December 31,2016)
Debt Instrument
Total long-term debt									€ 725	$ 849				€ 500	520
Interest rate, stated percentage									3.125%	3.125%		3.125%	3.125%			3.125%
Face Value | €												€ 225				€ 500
Net proceeds, after deducting debt issuance costs			$ 237	$ 520
Fair values of fixed rate debt obligations
Principal Amount										$ 866
Indicated Market Price (in dollars per share) | $ / shares										$ 105.34
Fair Value										$ 912
Senior Notes, 5.375% due 2025
Debt Instrument
Total long-term debt										$ 297					297
Interest rate, stated percentage									5.375%	5.375%
Fair values of fixed rate debt obligations
Principal Amount										$ 300
Indicated Market Price (in dollars per share) | $ / shares										$ 105.31
Fair Value										$ 316
Senior Notes 6.375%, due 2025
Debt Instrument
Total long-term debt										$ 295					294
Interest rate, stated percentage									6.375%	6.375%
Fair values of fixed rate debt obligations
Principal Amount										$ 300
Indicated Market Price (in dollars per share) | $ / shares										$ 112.62
Fair Value										$ 338
Senior Notes 4.00%, due 2023
Debt Instrument
Total long-term debt										$ 305
Interest rate, stated percentage									4.00%	4.00%
Face Value										$ 310
Net proceeds, after deducting debt issuance costs		$ 305
Fair values of fixed rate debt obligations
Principal Amount										$ 310
Indicated Market Price (in dollars per share) | $ / shares										$ 100.21
Fair Value										$ 311
Senior Debentures 7.80%, due 2018
Debt Instrument
Total long-term debt															250
Interest rate, stated percentage									7.80%	7.80%		7.80%	7.80%
Face Value													$ 228
Fair values of fixed rate debt obligations
Principal Amount											$ 22
Interest charges for note repurchase premiums and related write-off of unamortized finance fees					$ 18
Capital leases
Debt Instrument
Total long-term debt										$ 54					57
Other debt
Debt Instrument
Total long-term debt										17					26
Revolving Credit Facility | New Agreement
Debt Instrument
Total long-term debt										300
Multicurrency Revolving Credit Facility | New Agreement
Debt Instrument
Total long-term debt										600
Accounts Receivable Securitization Program
Accounts receivable securitization
Short-term loans and long-term debt due within one year										$ 133					$ 152
Weighted average interest rate, short-term debt (as a percent)									0.76%	0.76%				0.74%	0.74%
European Accounts Receivable Securitization Program
Accounts receivable securitization
Maximum Borrowing Capacity | €									€ 185
Minimum | Term Loan A | New Agreement
Debt Instrument
Interest rate margin, Eurocurrency Rate loans (as a percent)	1.25%
Interest rate margin, Base Rate loans (as a percent)	0.25%
Minimum | Revolving Credit Facility
Debt Instrument
Facility fee payable (as a percent)	0.20%
Maximum | Term Loan A | New Agreement
Debt Instrument
Interest rate margin, Eurocurrency Rate loans (as a percent)	1.75%
Interest rate margin, Base Rate loans (as a percent)	0.75%
Maximum | Revolving Credit Facility
Debt Instrument
Facility fee payable (as a percent)	0.30%