Borrowings and Credit Arrangements (Details) ¥ in Millions, £ in Millions		1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Aug. 20, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 GBP (£) units	Dec. 31, 2015	Dec. 31, 2018 USD ($) Days	Dec. 31, 2017 USD ($) units	Dec. 31, 2016 USD ($)	Dec. 31, 2018 USD ($) units	Dec. 31, 2018 JPY (¥) units	Dec. 19, 2018 USD ($)	Nov. 20, 2018 GBP (£)	Mar. 31, 2018 JPY (¥)	Feb. 26, 2018 USD ($)	Aug. 04, 2017 USD ($)	Apr. 10, 2015 USD ($)
Debt Instrument [Line Items]
Repurchase Agreement Counterparty, Amount at Risk								$ 1.01
Senior notes issued						$ 4,450,000,000
Schedule of debt maturities
Long-term Debt and Capital Lease Obligations						3,815,000,000		4,803,000,000
Borrowings and Credit Arrangements (Textuals) [Abstract]
Total debt						5,616,000,000		7,056,000,000
Debt, Current						$ 1,801,000,000		$ 2,253,000,000
Increase (Decrease) in Other Loans | £			£ 1,569
Weighted Average Maturity, Days | units			27			38		27	27
Interest Expense					$ 241,000,000	$ 229,000,000	$ 233,000,000
Credit and Security Facility, Aggregate Amount Terminated		$ 400,000,000
Borrowings [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Commercial Paper						1,197,000,000		$ 1,248,000,000
Commercial Paper [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Maximum Commercial Paper Outstanding with 2017 Facility						$ 2,250,000,000		$ 2,750,000,000
Short-term Debt, Weighted Average Interest Rate, at Point in Time			3.04%			1.85%		3.04%	3.04%
August 2019 Term Loan [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Short-term Debt	$ 1,000,000,000							$ 1,000,000,000
Debt Instrument, Basis Spread on Variable Rate	0.65%
Covenant Requirement [Member]
Summary of compliance with debt covenants
Maximum Leverage Ratio			3.75					3.75	3.75
Actual, Covenant [Member]
Summary of compliance with debt covenants
Maximum Leverage Ratio			2.56					2.56	2.56
Requirement, first two quarters following qualified acquisition [Member]
Summary of compliance with debt covenants
Maximum Leverage Ratio			4.75					4.75	4.75
Requirement, third quarter following qualified acquisition [Member]
Summary of compliance with debt covenants
Maximum Leverage Ratio			4.5					4.5	4.5
Requirement, fourth quarter following qualified acquisition [Member]
Summary of compliance with debt covenants
Maximum Leverage Ratio			4.25					4.25	4.25
Requirement, fifth quarter following qualified acquisition [Member]
Summary of compliance with debt covenants
Maximum Leverage Ratio			4.00					4.00	4.00
Requirement, sixth quarter and thereafter following qualified acquisition [Member]
Summary of compliance with debt covenants
Maximum Leverage Ratio			3.75					3.75	3.75
Commercial Paper [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Revolving credit facility						$ 1,053,000,000		$ 1,502,000,000
the 2017 Facility [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity														$ 2,250,000,000
the 2015 Facility [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Current interest rate on revolving credit facility				1.015%
Line of Credit Facility, Description				0.004
Commitment fee percentage				0.11%
Amount of exclusions from EBITDA related to existing restructuring plans															$ 500,000,000
Restructuring charges remaining to be excluded from calculation of consolidated EBITDA								350,000,000
Amount of exclusions from EBITDA related to future litigation charges and payments															$ 2,624,000,000
Legal payments remaining to be excluded from calculation of consolidated EBITDA								1,191,000,000
October 2018 Notes [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Debt, Current								$ 600,000,000
Debt Instrument, Interest Rate, Stated Percentage			(2.65%)					(2.65%)	(2.65%)
January 2020 Notes [Member]
Schedule of debt maturities
Payments due, Total						(850,000,000)		$ (850,000,000)
Borrowings and Credit Arrangements (Textuals) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage			(6.00%)					(6.00%)	(6.00%)
May 2020 Notes [Member]
Schedule of debt maturities
Payments due, Total						(600,000,000)		$ (600,000,000)
Borrowings and Credit Arrangements (Textuals) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage			(2.85%)					(2.85%)	(2.85%)
May 2022 Notes [Member]
Schedule of debt maturities
Payments due, Total						(500,000,000)		$ (500,000,000)
Borrowings and Credit Arrangements (Textuals) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage			(3.375%)					(3.375%)	(3.375%)
October 2023 Notes [Member]
Schedule of debt maturities
Payments due, Total						(450,000,000)		$ (450,000,000)
Borrowings and Credit Arrangements (Textuals) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage			(4.125%)					(4.125%)	(4.125%)
May 2025 Notes [Member]
Schedule of debt maturities
Payments due, Total						(750,000,000)		$ (750,000,000)
Borrowings and Credit Arrangements (Textuals) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage			(3.85%)					(3.85%)	(3.85%)
March 2028 Notes [Member]
Schedule of debt maturities
Payments due, Total						$ 0							$ (1,000,000,000)
Borrowings and Credit Arrangements (Textuals) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage			(2900000000.00%)			(2400000000.00%)		(2900000000.00%)	(2900000000.00%)				(4.00%)
November 2035 Notes [Member]
Schedule of debt maturities
Payments due, Total						$ (350,000,000)		$ (350,000,000)
Borrowings and Credit Arrangements (Textuals) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage			(7.00%)					(7.00%)	(7.00%)
January 2040 Notes [Member]
Schedule of debt maturities
Payments due, Total						(300,000,000)		$ (300,000,000)
Borrowings and Credit Arrangements (Textuals) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage			(7.375%)					(7.375%)	(7.375%)
Interest Rate Swap [Member]
Schedule of debt maturities
Payments due, Total						(38,000,000)		$ (26,000,000)
Capital Lease Obligations [Member]
Schedule of debt maturities
Payments due, Total						(1,000,000)		(6,000,000)
Senior Notes [Member]
Schedule of debt maturities
Payments due, Total						(4,400,000,000)		(4,800,000,000)
Yen Denominated Factoring Arrangements [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Maximum amount of proceeds from sale of finance receivables | ¥									¥ 22,000
Aggregate BTG Bridge [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Bridge Loan | £											£ 3,315
BTG Bridge, Debt Component [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Bridge Loan | £			£ 1,546								3,115
Days to Maturity, After Initial Borrowing | Days					364
Delayed Draw Term Loan [Member] | Aggregate Delayed Draw Term Loan [Member]
Schedule of debt maturities
Payments due, Total										$ (2,000,000,000)
Delayed Draw Term Loan [Member] | Debt Instrument, Redemption, Period Two [Member]
Schedule of debt maturities
Payments due, Total										(1,000,000,000)
Delayed Draw Term Loan [Member] | Debt Instrument, Redemption, Period Three [Member]
Schedule of debt maturities
Payments due, Total										$ (1,000,000,000)
BTG Bridge, Cash Component [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Bridge Loan | £											£ 200
Days to Maturity, After Initial Borrowing | Days					90
Euro Denominated Factoring Arrangements [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Maximum amount of proceeds from sale of finance receivables						456,000,000		474,000,000
De-recognized receivables						$ 171,000,000		165,000,000
Average interest rate of de-recognized receivables					2.70%	1.80%
Yen Denominated Factoring Arrangements [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Maximum amount of proceeds from sale of finance receivables						$ 195,000,000		273,000,000
De-recognized receivables						$ 157,000,000		$ 195,000,000
Average discounted rates of notes receivables			0.90%			1.30%		0.90%	0.90%
March 2018 Yen Factoring Program Max Capacity [Member]
Borrowings and Credit Arrangements (Textuals) [Abstract]
Maximum amount of proceeds from sale of finance receivables | ¥												¥ 30,000