Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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Percentage of principal amount of debt redeemed.

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The cash outflow for the extinguishment of long-term borrowing, with the highest claim on the assets of the entity in case of bankruptcy or liquidation, before its maturity.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

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DEBT - Senior Notes (Detail) - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
DEBT - Senior Notes (Detail) - USD ($)	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Percentage of principal amount that may be redeemed			100.00%
Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 4,770,000,000		$ 4,770,000,000	$ 3,792,000,000
Net proceeds from debt		$ 991,000,000	794,000,000
Early redemption of debt, amount			829,000,000
Loss on extinguishment of debt	17,000,000
Senior Notes \| $500 million, 7.20% due June 15, 2018
Debt Instrument [Line Items]
Long-term debt	0		0	501,000,000
Face amount	$ 500,000,000		$ 500,000,000
Debt instrument, stated interest rate	7.20%		7.20%
Debt redemption price, percentage	100.00%
Senior Notes \| $300 million, 6.30% due August 1, 2018
Debt Instrument [Line Items]
Long-term debt	$ 0		$ 0	304,000,000
Face amount	$ 300,000,000		$ 300,000,000
Debt instrument, stated interest rate	6.30%		6.30%
Senior Notes \| $400 million, 2.625% due October 1, 2019
Debt Instrument [Line Items]
Long-term debt	$ 399,000,000		$ 399,000,000	398,000,000
Face amount	$ 400,000,000		$ 400,000,000
Debt instrument, stated interest rate	2.625%		2.625%
Senior Notes \| $400 million, 2.50% due December 15, 2020
Debt Instrument [Line Items]
Long-term debt	$ 397,000,000		$ 397,000,000	0
Face amount	$ 400,000,000		$ 400,000,000
Debt instrument, stated interest rate	2.50%		2.50%
Senior Notes \| $400 million, 2.90% due December 15, 2022
Debt Instrument [Line Items]
Long-term debt	$ 396,000,000		$ 396,000,000	0
Face amount	$ 400,000,000		$ 400,000,000
Debt instrument, stated interest rate	2.90%		2.90%
Senior Notes \| $600 million, 3.15% due December 1, 2022
Debt Instrument [Line Items]
Long-term debt	$ 595,000,000		$ 595,000,000	595,000,000
Face amount	$ 600,000,000		$ 600,000,000
Debt instrument, stated interest rate	3.15%		3.15%
Senior Notes \| $600 million, 3.85% due October 1, 2024
Debt Instrument [Line Items]
Long-term debt	$ 595,000,000		$ 595,000,000	595,000,000
Face amount	$ 600,000,000		$ 600,000,000
Debt instrument, stated interest rate	3.85%		3.85%
Senior Notes \| $600 million, 3.95% due March 15, 2027
Debt Instrument [Line Items]
Long-term debt	$ 594,000,000		$ 594,000,000	0
Face amount	$ 600,000,000	$ 600,000,000	$ 600,000,000
Debt instrument, stated interest rate	3.95%	3.95%	3.95%
Senior Notes \| $250 million, 8.15% due June 15, 2038
Debt Instrument [Line Items]
Long-term debt	$ 263,000,000		$ 263,000,000	264,000,000
Face amount	$ 250,000,000		$ 250,000,000
Debt instrument, stated interest rate	8.15%		8.15%
Senior Notes \| $400 million, 4.625% due December 1, 2042
Debt Instrument [Line Items]
Long-term debt	$ 396,000,000		$ 396,000,000	396,000,000
Face amount	$ 400,000,000		$ 400,000,000
Debt instrument, stated interest rate	4.625%		4.625%
Senior Notes \| $750 million, 4.95% due October 1, 2044
Debt Instrument [Line Items]
Long-term debt	$ 739,000,000		$ 739,000,000	739,000,000
Face amount	$ 750,000,000		$ 750,000,000
Debt instrument, stated interest rate	4.95%		4.95%
Senior Notes \| $400 million, 4.80% due March 15, 2047
Debt Instrument [Line Items]
Long-term debt	$ 396,000,000		$ 396,000,000	$ 0
Face amount	$ 400,000,000	$ 400,000,000	$ 400,000,000
Debt instrument, stated interest rate	4.80%	4.80%	4.80%