Borrowings and Lines of Credit (Long-Term Debt) (Details) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
		Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Project financing obligations		$ 170	$ 170	$ 191
Other (including capitalized leases)		195	195	306
Total principal long-term debt		21,751	21,751	19,439
Other (fair market value adjustments and discounts)		33	33	60
Total long-term Debt		21,784	21,784	19,499
Less: current portion		1,654	1,654	179
Long-term debt, net of current portion		$ 20,130	$ 20,130	19,320
Notes 5.375% Due 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.375%	5.375%
Debt Instrument, Maturity Date, Description			2017
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 1,000	$ 1,000	1,000
Notes 1.800% Due 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.80%	1.80%
Debt Instrument, Maturity Date, Description			2017
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 1,500	$ 1,500	1,500
Junior subordinated notes 1.778% due 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.778%	1.778%
Debt Instrument, Maturity Date, Description			2018
Debt Instrument, Carrying Amount		$ 1,100	$ 1,100	1,100
Notes 6.800% Due 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.80%	6.80%
Debt Instrument, Maturity Date, Description			2018
Debt Instrument, Carrying Amount		$ 99	$ 99	99
Notes 6.125% Due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.125%	6.125%
Debt Instrument, Maturity Date, Description			2019
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 1,250	$ 1,250	1,250
Notes 8.875% Due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		8.875%	8.875%
Debt Instrument, Maturity Date, Description			2019
Debt Instrument, Carrying Amount		$ 271	$ 271	271
Notes 4.500% Due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.50%	4.50%
Debt Instrument, Maturity Date, Description			2020
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 1,250	$ 1,250	1,250
Notes 4.875% Due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.875%	4.875%
Debt Instrument, Maturity Date, Description			2020
Debt Instrument, Carrying Amount		$ 171	$ 171	171
Notes 8.750% Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		8.75%	8.75%
Debt Instrument, Maturity Date, Description			2021
Debt Instrument, Carrying Amount		$ 250	$ 250	250
Notes 3.100% Due 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.10%	3.10%
Debt Instrument, Maturity Date, Description			2022
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 2,300	$ 2,300	2,300
Notes 1.250% due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.25%	1.25%
Debt Instrument, Maturity Date, Description			2023
Debt Instrument, Call Feature			We may redeem these notes, in whole or in part, at our option at any time. If redeemed earlier than three months prior to the stated maturity date, the redemption price in Euro shall equal the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on an annual basis at a rate based upon a comparable German federal government bond whose maturity is closest to the maturity of the notes plus 15-30 basis points. In addition, the notes may be redeemed at our option in whole, but not in part, at any time in the event of certain developments affecting U.S. taxation
Debt Instrument, Carrying Amount	[2]	$ 829	$ 829	817
Notes 7.100% Due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		7.10%	7.10%
Debt Instrument, Maturity Date, Description			2027
Debt Instrument, Carrying Amount		$ 141	$ 141	141
Notes 6.700% Due 2028 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.70%	6.70%
Debt Instrument, Maturity Date, Description			2028
Debt Instrument, Carrying Amount		$ 400	$ 400	400
Notes 7.500% Due 2029 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		7.50%	7.50%
Debt Instrument, Maturity Date, Description			2029
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 550	$ 550	550
Notes 5.400% Due 2035 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.40%	5.40%
Debt Instrument, Maturity Date, Description			2035
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 600	$ 600	600
Notes 6.050% Due 2036 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.05%	6.05%
Debt Instrument, Maturity Date, Description			2036
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 600	$ 600	600
Notes 6.800% Due 2036 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.80%	6.80%
Debt Instrument, Maturity Date, Description			2036
Debt Instrument, Carrying Amount		$ 134	$ 134	134
Notes 7.000% Due 2038 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		7.00%	7.00%
Debt Instrument, Maturity Date, Description			2038
Debt Instrument, Carrying Amount		$ 159	$ 159	159
Notes 6.125% Due 2038 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.125%	6.125%
Debt Instrument, Maturity Date, Description			2038
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 1,000	$ 1,000	1,000
Notes 5.700% Due 2040 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.70%	5.70%
Debt Instrument, Maturity Date, Description			2040
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 1,000	$ 1,000	1,000
Notes 4.500% Due 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.50%	4.50%
Debt Instrument, Maturity Date, Description			2042
Debt Instrument, Call Feature			We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.
Debt Instrument, Carrying Amount	[1]	$ 3,500	$ 3,500	3,500
Notes 4.150% Due 2045 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.15%	4.15%
Debt Instrument, Maturity Date, Description			2045
Debt Instrument, Call Feature			We may redeem these notes, in whole or in part, at our option at any time. If redeemed prior to November 16, 2044, the redemption price in U.S. Dollars shall equal the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 25 basis points.
Debt Instrument, Carrying Amount	[3]	$ 850	$ 850	$ 850
Note 1.125% Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.125%	1.125%
Debt Instrument, Maturity Date, Description			2021
Debt Instrument, Call Feature			We may redeem these notes, in whole or in part, at our option at any time. If redeemed earlier than three months prior to the stated maturity date, the redemption price in Euro shall equal the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on an annual basis at a rate based upon a comparable German federal government bond whose maturity is closest to the maturity of the notes plus 15-30 basis points. In addition, the notes may be redeemed at our option in whole, but not in part, at any time in the event of certain developments affecting U.S. taxation.
Debt Instrument, Carrying Amount	[2]	$ 1,050	$ 1,050
Floating rate notes due 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date, Description			2018
Debt Instrument, Call Feature			These notes bear interest at the three-month EURIBOR rate plus 0.800%, established quarterly. The interest rate in effect at June 30, 2016 was 0.542%. The notes may be redeemed at our option in whole, but not in part, at any time in the event of certain developments affecting U.S. taxation.
Debt Instrument, Carrying Amount	[4]	$ 829	$ 829
Debt Instrument, Interest Rate Terms		Floating rate notes due 2018 (€750 million principal value)
Notes 1.875% Due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.875%	1.875%
Debt Instrument, Maturity Date, Description			2026
Debt Instrument, Call Feature			We may redeem these notes, in whole or in part, at our option at any time. If redeemed earlier than three months prior to the stated maturity date, the redemption price in Euro shall equal the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on an annual basis at a rate based upon a comparable German federal government bond whose maturity is closest to the maturity of the notes plus 15-30 basis points. In addition, the notes may be redeemed at our option in whole, but not in part, at any time in the event of certain developments affecting U.S. taxation
Debt Instrument, Carrying Amount		$ 553	$ 553

[1] We may redeem the above notes, in whole or in part, at our option at any time at a redemption price in U.S. Dollars equal to the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 10-50 basis points. The redemption price will also include interest accrued to the date of redemption on the principal balance of the notes being redeemed.

[2] We may redeem these notes, in whole or in part, at our option at any time. If redeemed earlier than three months prior to the stated maturity date, the redemption price in Euro shall equal the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on an annual basis at a rate based upon a comparable German federal government bond whose maturity is closest to the maturity of the notes plus 15-30 basis points. In addition, the notes may be redeemed at our option in whole, but not in part, at any time in the event of certain developments affecting U.S. taxation

[3] We may redeem these notes, in whole or in part, at our option at any time. If redeemed prior to November 16, 2044, the redemption price in U.S. Dollars shall equal the greater of 100% of the principal amount of the notes to be redeemed or the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semiannual basis at the adjusted treasury rate plus 25 basis points.

[4] These notes bear interest at the three-month EURIBOR rate plus 0.800%, established quarterly. The interest rate in effect at June 30, 2016 was 0.542%. The notes may be redeemed at our option in whole, but not in part, at any time in the event of certain developments affecting U.S. taxation.