Debt - Senior Notes and Contingent Convertible Senior Notes Purchased ( Table Phantom) (Details) In Millions, unless otherwise specified	12 Months Ended													12 Months Ended
	Dec. 31, 2011 USD ($)	Sep. 30, 2011	Dec. 31, 2012 Seven Point Six Two Five Percent Senior Notes Due Two Thousand Thirteen [Member]	Dec. 31, 2012 Nine Point Five Percent Senior Notes Due Two Thousand Fifteen [Member]	Dec. 31, 2012 Six Point Two Five Percent Euro Hyphen Denominated Senior Notes Due Two Thousand Seventeen [Member]	Dec. 31, 2012 Six Point Five Percent Senior Notes Due Two Thousand Seventeen [Member]	Dec. 31, 2012 Six Point Eight Seven Five Percent Senior Notes Due Two Thousand Eighteen [Member]	Dec. 31, 2012 Seven Point Two Five Percent Senior Notes Due Two Thousand Eighteen [Member]	Dec. 31, 2012 Six Point Six Two Five Percent Senior Notes Due Two Thousand Twenty [Member]	Dec. 31, 2012 Two Point Seven Five Percent Contingent Convertible Senior Notes Due Two Thousand Thirty Five [Member]	Dec. 31, 2012 Two Point Five Percent Contingent Convertible Senior Notes Due Two Thousand Thirty Seven [Member]	Dec. 31, 2012 Two Point Two Five Percent Contingent Convertible Senior Notes Due Two Thousand Thirty Eight [Member]	Dec. 31, 2011 Two Point Two Five Percent Contingent Convertible Senior Notes Due Two Thousand Thirty Eight [Member]	Dec. 31, 2011 Euro-Denominated Senior Notes EUR (€)	Dec. 31, 2011 Senior Notes USD ($)	Dec. 31, 2011 Senior Notes Seven Point Six Two Five Percent Senior Notes Due Two Thousand Thirteen [Member] USD ($)	Dec. 31, 2011 Senior Notes Nine Point Five Percent Senior Notes Due Two Thousand Fifteen [Member] USD ($)	Dec. 31, 2011 Senior Notes Six Point Two Five Percent Euro Hyphen Denominated Senior Notes Due Two Thousand Seventeen [Member] USD ($)		Dec. 31, 2011 Senior Notes Six Point Five Percent Senior Notes Due Two Thousand Seventeen [Member] USD ($)	Dec. 31, 2011 Senior Notes Six Point Eight Seven Five Percent Senior Notes Due Two Thousand Eighteen [Member] USD ($)	Dec. 31, 2011 Senior Notes Seven Point Two Five Percent Senior Notes Due Two Thousand Eighteen [Member] USD ($)	Dec. 31, 2011 Senior Notes Six Point Six Two Five Percent Senior Notes Due Two Thousand Twenty [Member] USD ($)	Dec. 31, 2011 Convertible Senior Notes USD ($)	Dec. 31, 2011 Convertible Senior Notes Two Point Seven Five Percent Contingent Convertible Senior Notes Due Two Thousand Thirty Five [Member] USD ($)	Dec. 31, 2011 Convertible Senior Notes Two Point Five Percent Contingent Convertible Senior Notes Due Two Thousand Thirty Seven [Member] USD ($)	Dec. 31, 2011 Convertible Senior Notes Two Point Two Five Percent Contingent Convertible Senior Notes Due Two Thousand Thirty Eight [Member] USD ($)
Long-Term Debt Instrument [Line Items]
Principal Amount Purchased	$ 1,904													€ 256	$ 1,373	$ 36	$ 160	$ 380	[1]	$ 440	$ 126	$ 131	$ 100	$ 531	$ 55	$ 210	$ 266
Foreign Currency Exchange Rate, Translation		1.4821
Debt Instrument Interest Rate Percentage			7.625%	9.50%	6.25%	6.50%	6.875%	7.25%	6.625%	2.75%	2.50%	2.25%
Debt Instrument Maturity Year			2013	2015	2017	2017	2018	2018	2020	2035	2037	2038	2038

[1] We purchased €256 million in aggregate principal amount of our euro-denominated senior notes which had a value of $380 million based on the exchange rate of $1.4821 to €1.00. Simultaneously with our purchase of the euro-denominated senior notes, we unwound cross currency swaps for the same principal amount. See Note 9 for additional information.