Fair values (Tables)

12 Months Ended

Dec. 31, 2015

Fair values

Fair value of financial assets and liabilities measured at fair value on a recurring basis

	December 31, 2015
($ in millions)	Level 1		Level 2		Level 3		Total fair value
Assets
Available-for-sale securities in "Cash and equivalents":
Debt securities—Corporate		—		11		—		11
Available-for-sale securities in "Marketable securities and short-term investments":
Equity securities		—		667		—		667
Debt securities—U.S. government obligations		121		—		—		121
Debt securities—Other government obligations		—		2		—		2
Debt securities—Corporate		—		508		—		508
Derivative assets—current in "Other current assets"		1		296		—		297
Derivative assets—non-current in "Other non-current assets"		—		186		—		186
Total		122		1,670		—		1,792
Liabilities
Derivative liabilities—current in "Other current liabilities"		3		315		—		318
Derivative liabilities—non-current in "Other non-current liabilities"		—		134		—		134
Total		3		449		—		452

	December 31, 2014
($ in millions)	Level 1		Level 2		Level 3		Total fair value
Assets
Available-for-sale securities in "Cash and equivalents":
Debt securities—Corporate		—		85		—		85
Available-for-sale securities in "Marketable securities and short-term investments":
Equity securities		—		110		—		110
Debt securities—U.S. government obligations		136		—		—		136
Debt securities—Other government obligations		—		2		—		2
Debt securities—Corporate		—		652		—		652
Derivative assets—current in "Other current assets"		—		289		—		289
Derivative assets—non-current in "Other non-current assets"		—		189		—		189
Total		136		1,327		—		1,463
Liabilities
Derivative liabilities—current in "Other current liabilities"		—		438		—		438
Derivative liabilities—non-current in "Other non-current liabilities"		—		108		—		108
Total		—		546		—		546

Schedule of fair values of financial instruments carried on a cost basis

	December 31, 2015
($ in millions)	Carrying value		Level 1		Level 2		Level 3		Total fair value
Assets
Cash and equivalents (excluding available-for-sale securities with original maturities up to 3 months):
Cash		1,837		1,837		—		—		1,837
Time deposits		2,717		—		2,717		—		2,717
Marketable securities and short-term investments (excluding available-for-sale securities):
Time deposits		104		—		104		—		104
Receivables under reverse repurchase agreements		224		—		224		—		224
Other short-term investments		7		7		—		—		7
Other non-current assets:
Loans granted		29		—		30		—		30
Held-to-maturity securities		99		—		110		—		110
Restricted cash and cash deposits		176		55		138		—		193
Liabilities
Short-term debt and current maturities of long-term debt (excluding capital lease obligations)		1,427		614		817		—		1,431
Long-term debt (excluding capital lease obligations)		5,889		5,307		751		—		6,058
Non-current deposit liabilities in "Other non-current liabilities"		215		—		244		—		244

	December 31, 2014
($ in millions)	Carrying value		Level 1		Level 2		Level 3		Total fair value
Assets
Cash and equivalents (excluding available-for-sale securities with original maturities up to 3 months):
Cash		2,218		2,218		—		—		2,218
Time deposits		3,140		—		3,140		—		3,140
Marketable securities and short-term investments (excluding available-for-sale securities):
Time deposits		200		—		200		—		200
Receivables under reverse repurchase agreements		219		—		219		—		219
Other short-term investments		6		6		—		—		6
Other non-current assets:
Loans granted		41		—		44		—		44
Held-to-maturity securities		95		—		109		—		109
Restricted cash and cash deposits		198		64		161		—		225
Liabilities
Short-term debt and current maturities of long-term debt (excluding capital lease obligations)		324		115		209		—		324
Long-term debt (excluding capital lease obligations)		7,198		6,148		1,404		—		7,552
Non-current deposit liabilities in "Other non-current liabilities"		222		—		267		—		267