Debt and Other Financing Arrangements - Credit Facilities (Details)		1 Months Ended	12 Months Ended
	Oct. 01, 2018 USD ($)	May 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Line of Credit Facility [Line Items]
Borrowing capacity			$ 5,054,000,000
Maximum Percentage Of Stock Of Certain First Tier Foreign Subsidiaries Pledged To Secure Senior Credit Facility			66.00%
Loss on extinguishment of debt			$ 10,000,000	$ 1,000,000	$ 24,000,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Loss on extinguishment of debt	$ 10,000,000	$ 1,000,000
Line of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	4,900,000,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Borrowing capacity	$ 1,500,000,000
Debt term	5 years
Revolving Credit Facility | Line of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	$ 1,500,000,000
Debt term	5 years
Term Loan A Facility
Line of Credit Facility [Line Items]
Borrowing capacity	$ 1,700,000,000
Debt term	5 years
Term Loan A Facility | Term Loan
Line of Credit Facility [Line Items]
Borrowing capacity	$ 1,700,000,000
Debt term	5 years
Term Loan B Facility
Line of Credit Facility [Line Items]
Borrowing capacity	$ 1,700,000,000
Debt term	7 years
Term Loan B Facility | Term Loan
Line of Credit Facility [Line Items]
Borrowing capacity	$ 1,700,000,000
Debt term	7 years
LIBOR | Term Loan A Facility | Term Loan
Line of Credit Facility [Line Items]
Variable rate	1.75%
LIBOR | Term Loan B Facility | Term Loan
Line of Credit Facility [Line Items]
Variable rate	2.75%
Debt Covenant, Term 1 | Line of Credit
Line of Credit Facility [Line Items]
Consolidated Net Leverage Ratio	4.0
Debt Covenant, Term 1 | LIBOR | Term Loan B Facility | Term Loan
Line of Credit Facility [Line Items]
Variable rate	3.00%
Debt Covenant, Term 2 | Line of Credit
Line of Credit Facility [Line Items]
Consolidated Net Leverage Ratio	3.75
Debt Covenant, Term 3 | Line of Credit
Line of Credit Facility [Line Items]
Consolidated Net Leverage Ratio	3.5
Debt Covenant, Term 4 | Line of Credit
Line of Credit Facility [Line Items]
Consolidated Net Leverage Ratio	2.75