Borrowings and Lines of Credit (Summary of Debt Instruments Redeemed and Tender Offers Completed) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Total of make-whole premiums paid to redeem notes	$ 179	$ 179
Total of premiums paid on tender offer	43	$ 43
Total cash paid for debt redemption	1,707
Notes 7.375 Percent Due 2016
Debt Instrument [Line Items]
Early repayment of long-term debt, principal amount	$ 146
Debt instrument, interest rate, stated percentage	7.375%
Notes 6.875 Percent Due 2017
Debt Instrument [Line Items]
Early repayment of long-term debt, principal amount	$ 75
Debt instrument, interest rate, stated percentage	6.875%
Notes 6.65 Percent Due 2018
Debt Instrument [Line Items]
Early repayment of long-term debt, principal amount	$ 575
Debt instrument, interest rate, stated percentage	6.65%
Notes 7.4 Percent Due 2019
Debt Instrument [Line Items]
Early repayment of long-term debt, principal amount	$ 199
Debt instrument, interest rate, stated percentage	7.40%
Notes 2.70 Percent Due 2022
Debt Instrument [Line Items]
Early repayment of long-term debt, principal amount	$ 400
Debt instrument, interest rate, stated percentage	2.70%
Non-callable Debentures 9 Percent Due 2021
Debt Instrument [Line Items]
Early repayment of long-term debt, principal amount	$ 16
Debt instrument, interest rate, stated percentage	9.00%
Notes 7.70 Percent Due 2038
Debt Instrument [Line Items]
Early repayment of long-term debt, principal amount	$ 74
Debt instrument, interest rate, stated percentage	7.70%

The cash outflow from the early repayment of the principal amount of a long-term borrowing.

No definition available.

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- Definition

The cash outflow for prepayment premiums to early retire long-term debt consisting of public notes

+ References

No definition available.

+ Details

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- Definition

The cash outflow for prepayment premiums to early retirement long-term via tender offer.

+ References

No definition available.

+ Details

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The cash outflow for incremental, external costs directly pertaining to an early extinguishment of debt, including legal costs and prepayment penalties, and excluding interest and repayment of debt principal.

+ References

No definition available.

+ Details

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