Summary of Accounting Policies - Error Correction, Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating Activities
Net income (loss)	$ 45	$ 63	$ (60)	$ 137
Net cash provided by (used by) operating activities				78
Investing Activities
Net cash used by investing activities				(101)
Financing Activities
Proceeds from term loans and notes			111	9
Repayments of term loans and notes			(190)	(28)
Retirement of long-term debt				0
Borrowings on revolving lines of credit			4,525	2,669
Payments on revolving lines of credit			(4,254)	(2,614)
Net increase (decrease) in revolver borrowings				0
Issuance (repurchase) of common shares			(2)	(1)
Cash dividends			(20)	(25)
Debt issuance cost of long-term debt				0
Purchase of common stock under the share repurchase program				0
Net increase (decrease) in bank overdrafts			(8)	(7)
Net increase (decrease) in short-term borrowings secured by accounts receivable				0
Other			(1)	(22)
Distributions to noncontrolling interest partners			(20)	(28)
Net cash provided (used) by financing activities				(47)
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash			11	(11)
Increase (decrease) in cash, cash equivalents and restricted cash			(312)	(81)
Cash, cash equivalents and restricted cash, beginning of period			702	318
Cash, cash equivalents and restricted cash, end of period	$ 390	237	$ 390	237
As Reported
Operating Activities
Net income (loss)		66		138
Net cash provided by (used by) operating activities				78
Investing Activities
Net cash used by investing activities				(101)
Financing Activities
Proceeds from term loans and notes				0
Repayments of term loans and notes				0
Retirement of long-term debt				(12)
Borrowings on revolving lines of credit				0
Payments on revolving lines of credit				0
Net increase (decrease) in revolver borrowings				48
Issuance (repurchase) of common shares				(1)
Cash dividends				(25)
Debt issuance cost of long-term debt				(2)
Purchase of common stock under the share repurchase program				0
Net increase (decrease) in bank overdrafts				(7)
Net increase (decrease) in short-term borrowings secured by accounts receivable				(20)
Other				0
Distributions to noncontrolling interest partners				(28)
Net cash provided (used) by financing activities				(47)
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash				(11)
Increase (decrease) in cash, cash equivalents and restricted cash				(81)
Cash, cash equivalents and restricted cash, beginning of period				318
Cash, cash equivalents and restricted cash, end of period		237		237
Reclasses
Operating Activities
Net income (loss)		0		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				(12)
Retirement of long-term debt				12
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
Debt issuance cost of long-term debt				2
Purchase of common stock under the share repurchase program				0
Net increase (decrease) in bank overdrafts				0
Net increase (decrease) in short-term borrowings secured by accounts receivable				20
Other				(22)
Distributions to noncontrolling interest partners				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		0
As Reclassified
Operating Activities
Net income (loss)		66		138
Net cash provided by (used by) operating activities				78
Investing Activities
Net cash used by investing activities				(101)
Financing Activities
Proceeds from term loans and notes				0
Repayments of term loans and notes				(12)
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				48
Issuance (repurchase) of common shares				(1)
Cash dividends				(25)
Debt issuance cost of long-term debt				0
Purchase of common stock under the share repurchase program				0
Net increase (decrease) in bank overdrafts				(7)
Net increase (decrease) in short-term borrowings secured by accounts receivable				0
Other				(22)
Distributions to noncontrolling interest partners				(28)
Net cash provided (used) by financing activities				(47)
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash				(11)
Increase (decrease) in cash, cash equivalents and restricted cash				(81)
Cash, cash equivalents and restricted cash, beginning of period				318
Cash, cash equivalents and restricted cash, end of period		237		237
Revisions
Operating Activities
Net income (loss)		(3)		(1)
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				9
Repayments of term loans and notes				(16)
Retirement of long-term debt				0
Borrowings on revolving lines of credit				2,669
Payments on revolving lines of credit				(2,614)
Net increase (decrease) in revolver borrowings				(48)
Issuance (repurchase) of common shares				0
Cash dividends				0
Debt issuance cost of long-term debt				0
Purchase of common stock under the share repurchase program				0
Net increase (decrease) in bank overdrafts				0
Net increase (decrease) in short-term borrowings secured by accounts receivable				0
Other				0
Distributions to noncontrolling interest partners				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		$ 0