Summary of Accounting Policies - Error Correction, Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Activities
Net income (loss)	$ (105)	$ 74
Net cash provided by (used by) operating activities		0
Investing Activities
Net cash used by investing activities		(53)
Financing Activities
Proceeds from term loans and notes	28	6
Repayments of term loans and notes	(64)	(13)
Retirement of long-term debt		0
Borrowings on revolving lines of credit	2,119	1,267
Payments on revolving lines of credit	(1,981)	(1,189)
Net increase (decrease) in revolver borrowings		0
Issuance (repurchase) of common shares	(2)	(2)
Cash dividends	(20)	(13)
Net increase (decrease) in bank overdrafts	(1)	(4)
Net increase (decrease) in short-term borrowings secured by accounts receivable		0
Other	(3)	(30)
Net cash provided (used) by financing activities		22
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash	19	3
Increase (decrease) in cash, cash equivalents and restricted cash	(339)	(28)
Cash, cash equivalents and restricted cash, beginning of period	702	318
Cash, cash equivalents and restricted cash, end of period	$ 363	290
As Reported
Operating Activities
Net income (loss)		72
Net cash provided by (used by) operating activities		0
Investing Activities
Net cash used by investing activities		(53)
Financing Activities
Proceeds from term loans and notes		0
Repayments of term loans and notes		0
Retirement of long-term debt		(6)
Borrowings on revolving lines of credit		0
Payments on revolving lines of credit		0
Net increase (decrease) in revolver borrowings		77
Issuance (repurchase) of common shares		(2)
Cash dividends		(13)
Net increase (decrease) in bank overdrafts		(4)
Net increase (decrease) in short-term borrowings secured by accounts receivable		(30)
Other		0
Net cash provided (used) by financing activities		22
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash		3
Increase (decrease) in cash, cash equivalents and restricted cash		(28)
Cash, cash equivalents and restricted cash, beginning of period		318
Cash, cash equivalents and restricted cash, end of period		290
Reclasses
Operating Activities
Net income (loss)		0
Net cash provided by (used by) operating activities		0
Investing Activities
Net cash used by investing activities		0
Financing Activities
Proceeds from term loans and notes		0
Repayments of term loans and notes		(6)
Retirement of long-term debt		6
Borrowings on revolving lines of credit		0
Payments on revolving lines of credit		0
Net increase (decrease) in revolver borrowings		0
Issuance (repurchase) of common shares		0
Cash dividends		0
Net increase (decrease) in bank overdrafts		0
Net increase (decrease) in short-term borrowings secured by accounts receivable		30
Other		(30)
Net cash provided (used) by financing activities		0
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash		0
Increase (decrease) in cash, cash equivalents and restricted cash		0
Cash, cash equivalents and restricted cash, beginning of period		0
Cash, cash equivalents and restricted cash, end of period		0
As Reclassified
Operating Activities
Net income (loss)		72
Net cash provided by (used by) operating activities		0
Investing Activities
Net cash used by investing activities		(53)
Financing Activities
Proceeds from term loans and notes		0
Repayments of term loans and notes		(6)
Retirement of long-term debt		0
Borrowings on revolving lines of credit		0
Payments on revolving lines of credit		0
Net increase (decrease) in revolver borrowings		77
Issuance (repurchase) of common shares		(2)
Cash dividends		(13)
Net increase (decrease) in bank overdrafts		(4)
Net increase (decrease) in short-term borrowings secured by accounts receivable		0
Other		(30)
Net cash provided (used) by financing activities		22
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash		3
Increase (decrease) in cash, cash equivalents and restricted cash		(28)
Cash, cash equivalents and restricted cash, beginning of period		318
Cash, cash equivalents and restricted cash, end of period		290
Revisions
Operating Activities
Net income (loss)		2
Net cash provided by (used by) operating activities		0
Investing Activities
Net cash used by investing activities		0
Financing Activities
Proceeds from term loans and notes		6
Repayments of term loans and notes		(7)
Retirement of long-term debt		0
Borrowings on revolving lines of credit		1,267
Payments on revolving lines of credit		(1,189)
Net increase (decrease) in revolver borrowings		(77)
Issuance (repurchase) of common shares		0
Cash dividends		0
Net increase (decrease) in bank overdrafts		0
Net increase (decrease) in short-term borrowings secured by accounts receivable		0
Other		0
Net cash provided (used) by financing activities		0
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash		0
Increase (decrease) in cash, cash equivalents and restricted cash		0
Cash, cash equivalents and restricted cash, beginning of period		0
Cash, cash equivalents and restricted cash, end of period		$ 0