Debt (Schedule Of Long-Term Debt) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Total long-term debt	$ 3,458	$ 2,391
Less current portion of long-term debt	76	27
Total debt	3,382	2,364
Debentures, 6.75%, Due 2013 [Member]
Debt Instrument [Line Items]
Total debt	49	100
Interest rate on debt	6.75%
Debt maturity date	2013
Debentures, 5.90%, Due 2014 [Member]
Debt Instrument [Line Items]
Total debt		100
Interest rate on debt	5.90%
Debt maturity date	2014
Debentures, 6.20%, Due 2016 [Member]
Debt Instrument [Line Items]
Total debt		75
Interest rate on debt	6.20%
Debt maturity date	2016
Debentures, 8.875%, Due 2016 [Member]
Debt Instrument [Line Items]
Total debt	68	81
Interest rate on debt	8.875%
Debt maturity date	2016
Debentures, 1.45% percentage, Due 2017 [Member]
Debt Instrument [Line Items]
Total debt	249
Interest rate on debt	1.45%
Debt maturity date	2017
Debentures, 6.625%, Due 2019 [Member]
Debt Instrument [Line Items]
Total debt	250	250
Interest rate on debt	6.625%
Debt maturity date	2019
Debentures, 4.25%, Due 2020 [Member]
Debt Instrument [Line Items]
Total debt	297	298
Interest rate on debt	4.25%
Debt maturity date	2020
Debentures, 8.875%, Due 2021 [Member]
Debt Instrument [Line Items]
Total debt	71	87
Interest rate on debt	8.875%
Debt maturity date	2021
Medium-Term Notes, Average Rate 7.66%, Due Through 2023 [Member]
Debt Instrument [Line Items]
Total debt	45	45
Interest rate on debt	7.66%
Debt maturity date	2023
Debentures, 7.00%, Due 2024 [Member]
Debt Instrument [Line Items]
Total debt	99	99
Interest rate on debt	7.00%
Debt maturity date	2024
Debentures, 6.85%, Due 2029 [Member]
Debt Instrument [Line Items]
Total debt	173	175
Interest rate on debt	6.85%
Debt maturity date	2029
Debentures, Callable, 7.25%, Due 2036 [Member]
Debt Instrument [Line Items]
Total debt	249	249
Interest rate on debt	7.25%
Debt maturity date	2036
Debentures, 4.70%, Due 2037 [Member]
Debt Instrument [Line Items]
Total debt	250
Interest rate on debt	4.70%
Debt maturity date	2037
Debentures, 5.75%, Due 2040 [Member]
Debt Instrument [Line Items]
Total debt	398	397
Interest rate on debt	5.75%
Debt maturity date	2040
Debentures, 4.75%, Due 2042 [Member]
Debt Instrument [Line Items]
Total debt	500
Interest rate on debt	4.75%
Debt maturity date	2042
Other Average Rate 6.00%, Due Through 2037 [Member]
Debt Instrument [Line Items]
Total debt	$ 760	$ 435
Interest rate on debt	6.00%
Debt maturity date	2037