Schedule I - Condensed Financial Information of Parent\ (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current Assets:
Cash and cash equivalents	$ 1,970				$ 1,695				$ 1,970	$ 1,695	$ 2,506
Restricted cash	751				477				751	477
Deferred income taxes	222				454				222	454
Total current assets	8,465				9,229				8,465	9,229
Noncurrent Assets:
Investment in and advances to subsidiaries and affiliates	1,196				1,422				1,196	1,422	1,320
Office equipment:
Cost	31,837				31,068				31,837	31,068
Accumulated depreciation	(9,723)				(8,944)				(9,723)	(8,944)
Office equipment, net	25,913				25,001				25,913	25,001
Other assets:
Deferred income taxes	996				715				996	715
Debt service reserves and other deposits	2,242				2,346				2,242	2,346
Total other assets	7,452				11,116				7,452	11,116
TOTAL ASSETS	41,830				45,346				41,830	45,346	40,511
Current Liabilities:
Accounts payable	2,638				2,008				2,638	2,008
Accrued and other liabilities	2,532				3,389				2,532	3,389
Total current liabilities	8,319				8,438				8,319	8,438
Long-term Liabilities:
Other long-term liabilities	3,706				3,111				3,706	3,111
Total noncurrent liabilities	25,919				27,101				25,919	27,101
Stockholders' equity:
Common stock	8				8				8	8
Additional paid-in capital	8,525				8,507				8,525	8,507
Retained earnings	(264)				678				(264)	678
Accumulated other comprehensive loss	(2,920)				(2,758)				(2,920)	(2,758)
Treasury stock, at cost (66,415,984 and 42,386,961 shares at December 31, 2012 and 2011, respectively)	(780)				(489)				(780)	(489)
Total stockholders' equity	4,569				5,946				4,569	5,946
Total	41,830				45,346				41,830	45,346
Statements of Unconsolidated Operations
Interest income									349	399	407
General and administrative expenses									(301)	(391)	(391)
Interest expense									(1,572)	(1,553)	(1,449)
Income tax benefit (expense)									708	634	593
Net income (loss)	175	(1,568)	140	341	(209)	(131)	174	224	(912)	58	9
Condensed Financial Information Of Parent Company Only Statement Of Comprehensive Income [Abstract]
Net income (loss)	323	(1,402)	207	515	445	175	427	483	(357)	1,530	1,059
Available-for-sale securities activity:
Change in fair value of available-for-sale securities, net of income tax (expense) benefit of $0, $0 and $3, respectively									1	1	(5)
Reclassification to earnings, net of income tax (expense) benefit of $0, $0 and $0, respectively									1	2	0
Total change in fair value of available-for-sale securities									0	(1)	(5)
Foreign currency translation activity:
Foreign currency translation adjustments, net of income tax (expense) benefit of $0, $18 and $(11), respectively									(247)	(484)	468
Reclassification to earnings, net of income tax (expense) benefit of $0, $0 and $0, respectively									(37)	(188)	(142)
Total foreign currency translation adjustments									(210)	(296)	610
Derivative activity:
Change in derivative fair value, net of income tax (expense) benefit of $33, $95 and $37, respectively									(134)	(379)	(242)
Reclassification to earnings, net of income tax (expense) benefit of $(51), $(21) and $(20), respectively									(177)	(137)	(162)
Total change in fair value of derivatives									43	(242)	(80)
Pension activity:
Prior service cost for the period, net of income tax benefit (expense) of $0, $0 and $0, respectively									(1)	0	0
Net actuarial gain (loss) for the period, net of income tax (expense) benefit of $64, $25 and $23, respectively									(587)	(223)	(111)
Amortization of net actuarial loss, net of income tax (expense) benefit of $(5), $(1) and $(12), respectively									24	13	23
Total change in unfunded pension obligation									(564)	(210)	(88)
OTHER COMPREHENSIVE INCOME (LOSS)									(731)	(749)	437
COMPREHENSIVE INCOME (LOSS)									(1,088)	781	1,496
Condensed Financial Information Of Parent Company Only Unconsolidated Cash Flows [Abstract]
Net cash provided by operating activities									2,901	2,884	3,465
Investing activities:
(Increase) decrease in restricted cash									(43)	61	(104)
Acquisitions - net of cash acquired									(20)	(3,562)	(254)
Net cash used in investing activities									(1,023)	(4,906)	(2,040)
Financing activities:
Borrowings under the revolving credit facilities, net									(321)	437	78
Proceeds from issuance of common stock									0	0	1,567
Common stock dividends paid									(30)	0	0
Purchase of treasury stock									(301)	(279)	(99)
Payments for financing fees									(40)	(202)	(61)
Net cash (used in) provided by financing activities									(1,739)	1,412	(706)
Total increase (decrease) in cash and cash equivalents									275	(811)	761
Cash and cash equivalents, beginning				1,695				2,506	1,695	2,506	1,745
Cash and cash equivalents, ending	1,970				1,695				1,970	1,695	2,506
Supplemental disclosures:
Cash payments for interest, net of amounts capitalized									1,509	1,442	1,462
Cash payments for income taxes, net of refunds									647	971	698
Error Corrections and Prior Period Adjustments, Description									Correction of an Error – Certain amounts due to or from subsidiaries were not properly eliminated in the preparation of the Schedule I Condensed Financial Information of Parent for the year ended December 31, 2011 included in the Company’s 2011 Form 10-K.  As a result, the December 31, 2011 balance sheet information of accounts and notes receivable from subsidiaries, investments in and advances to subsidiaries and affiliates, and current and long-term accounts and notes payable to subsidiaries were overstated.    Accounts and notes receivable from subsidiaries was previously reported as $871 million and has been restated to $602 million.  Investment in and advances to subsidiaries and affiliates was previously reported as $12,088 million and has been restated to $11,352 million.  Accrued and notes payable to subsidiaries was previously reported as $317 million and has been restated to $48 million.  Accounts and notes payable to subsidiaries was previously reported as $1,007 million and has been restated to $254 million. Net cash provided by operating activities previously reported on the statement of cash flows for the year ended December 31, 2011 was previously reported as $1,569 million and has now been restated to $719 million.  Net cash used in investing activities was previously reported as $2,747 million and has now been restated to $2,638 million.  Net cash provided by financing activities previously reported as $773 million was restated to $1,512 million. Interest income and interest expense previously reported on the statement of operations for the year ended December 31, 2011 were each reduced by approximately $50 million as a result of these adjustments. There was no impact to Parent Company net income. There was no impact to the Schedule 1 Condensed Financial Information of Parent for the twelve months ended December 31, 2010 or the statement of comprehensive income for the year ended December 31, 2011 as a result of these adjustments. Further, there was no impact to the Company’s consolidated financial statements for 2012, 2011 or 2010 as a result of these adjustments.
Recourse Debt
Recourse debt	5,962				6,485				5,962	6,485
Current maturities of recourse debt	11				305				11	305
Recourse debt - noncurrent	5,951				6,180				5,951	6,180
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	5,962				6,485				5,962	6,485
Guarantees
Guarantees and Letters of Credit
Obligations Maximum Exposure Total	568								568
Number of Agreements	19								19
Letters of credit under secured credit facility
Guarantees and Letters of Credit
Obligations Maximum Exposure Total	5								5
Number of Agreements	6								6
Cash Collateralized Letters Of Credit [Member]
Guarantees and Letters of Credit
Obligations Maximum Exposure Total	215								215
Number of Agreements	9								9
Senior Unsecured Note 775 Due 2014 [Member]
Recourse Debt
Recourse debt	500				500				500	500
Interest Rate	7.75%								7.75%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	500				500				500	500
Senior Unsecured Note 775 Due 2015 [Member]
Recourse Debt
Recourse debt	500				500				500	500
Interest Rate	7.75%								7.75%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	500				500				500	500
Revolving Credit Loan Facility LIBOR Plus 300 Due 2015 [Member]
Recourse Debt
Recourse debt	0				295				0	295
Interest Rate - Percent Over LIBOR	3.00%								3.00%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	0				295				0	295
Senior Unsecured Note 975 Due 2016 [Member]
Recourse Debt
Recourse debt	535				535				535	535
Interest Rate	9.75%								9.75%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	535				535				535	535
Senior Unsecured Note 800 Due 2017 [Member]
Recourse Debt
Recourse debt	1,500				1,500				1,500	1,500
Interest Rate	8.00%								8.00%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	1,500				1,500				1,500	1,500
Senior Secured Term Loan LIBOR Plus 325 Due 2018 [Member]
Recourse Debt
Recourse debt	807				1,042				807	1,042
Interest Rate - Percent Over LIBOR	3.25%								3.25%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	807				1,042				807	1,042
Senior Unsecured Note 800 Due 2020 [Member]
Recourse Debt
Recourse debt	625				625				625	625
Interest Rate	8.00%								8.00%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	625				625				625	625
Senior Unsecured Note 7375 Due 2021 [Member]
Recourse Debt
Recourse debt	1,000				1,000				1,000	1,000
Interest Rate	7.38%								7.38%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	1,000				1,000				1,000	1,000
Term Convertible Trust Securities 675 Due 2029 [Member]
Recourse Debt
Recourse debt	517				517				517	517
Interest Rate	6.75%								6.75%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	517				517				517	517
Unamortized Discounts [Member]
Recourse Debt
Recourse debt	(22)				(29)				(22)	(29)
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	(22)				(29)				(22)	(29)
Parent Company
Current Assets:
Cash and cash equivalents	305				189				305	189	594
Restricted cash	227				50				227	50
Accounts and notes receivable from subsidiaries	594				602				594	602
Deferred income taxes	8				24				8	24
Prepaid Expense and Other Assets, Current	28				43				28	43
Total current assets	1,162				908				1,162	908
Noncurrent Assets:
Investment in and advances to subsidiaries and affiliates	9,393				11,352				9,393	11,352
Office equipment:
Cost	86				81				86	81
Accumulated depreciation	(72)				(67)				(72)	(67)
Office equipment, net	14				14				14	14
Other assets:
Deferred financing costs (net of accumulated amortization of $58 and $74, respectively)	76				92				76	92
Deferred income taxes	573				525				573	525
Debt service reserves and other deposits	0				222				0	222
Total other assets	649				839				649	839
TOTAL ASSETS	11,218				13,113				11,218	13,113
Current Liabilities:
Accounts payable	15				21				15	21
Accounts and notes payable to subsidiaries	50				48				50	48
Accrued and other liabilities	241				216				241	216
Senior notes payable - current portion	11				305				11	305
Total current liabilities	317				590				317	590
Long-term Liabilities:
Senior notes payable	5,434				5,663				5,434	5,663
Junior subordinated notes and debentures payable	517				517				517	517
Accounts and notes payable to subsidiaries	242				254				242	254
Other long-term liabilities	139				143				139	143
Total noncurrent liabilities	6,332				6,577				6,332	6,577
Stockholders' equity:
Common stock	8				8				8	8
Additional paid-in capital	8,525				8,507				8,525	8,507
Retained earnings	(264)				678				(264)	678
Accumulated other comprehensive loss	(2,920)				(2,758)				(2,920)	(2,758)
Treasury stock, at cost (66,415,984 and 42,386,961 shares at December 31, 2012 and 2011, respectively)	(780)				(489)				(780)	(489)
Total stockholders' equity	4,569				5,946				4,569	5,946
Total	11,218				13,113				11,218	13,113
Condensed Financial Information Of Parent Company Only Unconsolidated Balance Sheets Parentheticals [Abstract]
Deferred financing costs, accumulated amortization	58				74				58	74
Statements of Unconsolidated Operations
Revenues from subsidiaries and affiliates									20	59	34
Equity In Earnings Of Subsidiaries And Affiliates									(437)	352	590
Interest income									119	158	279
General and administrative expenses									(133)	(241)	(261)
Interest expense									(502)	(444)	(461)
Income (loss) before income taxes									(933)	(116)	181
Income tax benefit (expense)									(21)	(174)	172
Net income (loss)									(912)	58	9
Available-for-sale securities activity:
Change in fair value of available-for-sale securities, net of income tax (expense) benefit of $0, $0 and $3, respectively									1	1	(5)
Reclassification to earnings, net of income tax (expense) benefit of $0, $0 and $0, respectively									1	2	0
Total change in fair value of available-for-sale securities									0	(1)	(5)
Foreign currency translation activity:
Foreign currency translation adjustments, net of income tax (expense) benefit of $0, $18 and $(11), respectively									(127)	(297)	383
Reclassification to earnings, net of income tax (expense) benefit of $0, $0 and $0, respectively									(37)	(154)	(103)
Total foreign currency translation adjustments									(90)	(143)	486
Derivative activity:
Change in derivative fair value, net of income tax (expense) benefit of $33, $95 and $37, respectively									(108)	(311)	(252)
Reclassification to earnings, net of income tax (expense) benefit of $(51), $(21) and $(20), respectively									(161)	(121)	(172)
Total change in fair value of derivatives									53	(190)	(80)
Pension activity:
Prior service cost for the period, net of income tax benefit (expense) of $0, $0 and $0, respectively									(1)	0	0
Net actuarial gain (loss) for the period, net of income tax (expense) benefit of $64, $25 and $23, respectively									(130)	(43)	(23)
Amortization of net actuarial loss, net of income tax (expense) benefit of $(5), $(1) and $(12), respectively									6	2	1
Total change in unfunded pension obligation									(125)	(41)	(22)
OTHER COMPREHENSIVE INCOME (LOSS)									(162)	(375)	379
COMPREHENSIVE INCOME (LOSS)									(1,074)	(317)	388
Condensed Financial Information Of Parent Company Only Unconsolidated Cash Flows [Abstract]
Net cash provided by operating activities									694	719	488
Investing activities:
Investment in and advances to subsidiaries									168	2,655	1,185
Return of capital									660	304	300
(Increase) decrease in restricted cash									44	(261)	(2)
Additions to property, plant and equipment									24	28	22
Acquisitions - net of cash acquired									1	2	(3)
Net cash used in investing activities									513	(2,638)	(912)
Financing activities:
Borrowings of notes payable and other coupon bearing securities									0	2,050	0
Borrowings under the revolving credit facilities, net									(295)	295	0
Repayments of Long-term Debt									236	477	914
Loans from subsidiaries									(236)	(5)	(154)
Proceeds from issuance of common stock									8	3	1,569
Purchase of treasury stock									(301)	(279)	(99)
Payments for financing fees									(1)	(75)	(12)
Net cash (used in) provided by financing activities									(1,091)	1,512	390
Total increase (decrease) in cash and cash equivalents									116	(405)	(34)
Cash and cash equivalents, beginning				189				594	189	594	628
Cash and cash equivalents, ending	305				189				305	189	594
Supplemental disclosures:
Cash payments for interest, net of amounts capitalized									479	392	412
Cash payments for income taxes, net of refunds									0	(6)	0
Recourse Debt
Recourse debt	5,962				6,485				5,962	6,485
Current maturities of recourse debt	(11)				(305)				(11)	(305)
Recourse debt - noncurrent	5,951				6,180				5,951	6,180
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
2013	11								11
2014	510								510
2015	511								511
2016	527								527
2017	1,510								1,510
Thereafter	2,893								2,893
Total debt	5,962				6,485				5,962	6,485
Dividends From Subsidiaries and Affiliates
Subsidiaries									1,049	1,059	944
Affiliates									5	25	10
Guarantees and Letters of Credit
Letter of credit fee range (minimum)									0.25%
Letter of credit fee range (maximum)									3.25%
Parent Company | Senior Unsecured Note 775 Due 2014 [Member]
Recourse Debt
Recourse debt	500				500				500	500
Interest Rate	7.75%								7.75%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	500				500				500	500
Parent Company | Senior Unsecured Note 775 Due 2015 [Member]
Recourse Debt
Recourse debt	500				500				500	500
Interest Rate	7.75%								7.75%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	500				500				500	500
Parent Company | Revolving Credit Loan Facility LIBOR Plus 300 Due 2015 [Member]
Recourse Debt
Recourse debt	0				295				0	295
Interest Rate - Percent Over LIBOR	3.00%								3.00%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	0				295				0	295
Parent Company | Senior Unsecured Note 975 Due 2016 [Member]
Recourse Debt
Recourse debt	535				535				535	535
Interest Rate	9.75%								9.75%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	535				535				535	535
Parent Company | Senior Unsecured Note 800 Due 2017 [Member]
Recourse Debt
Recourse debt	1,500				1,500				1,500	1,500
Interest Rate	8.00%								8.00%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	1,500				1,500				1,500	1,500
Parent Company | Senior Secured Term Loan LIBOR Plus 325 Due 2018 [Member]
Recourse Debt
Recourse debt	807				1,042				807	1,042
Interest Rate - Percent Over LIBOR	3.25%								3.25%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	807				1,042				807	1,042
Parent Company | Senior Unsecured Note 800 Due 2020 [Member]
Recourse Debt
Recourse debt	625				625				625	625
Interest Rate	8.00%								8.00%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	625				625				625	625
Parent Company | Senior Unsecured Note 7375 Due 2021 [Member]
Recourse Debt
Recourse debt	1,000				1,000				1,000	1,000
Interest Rate	7.38%								7.38%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	1,000				1,000				1,000	1,000
Parent Company | Term Convertible Trust Securities 675 Due 2029 [Member]
Recourse Debt
Recourse debt	517				517				517	517
Interest Rate	6.75%								6.75%
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	517				517				517	517
Parent Company | Unamortized Discounts [Member]
Recourse Debt
Recourse debt	(22)				(29)				(22)	(29)
Condensed Financial Information Of Parent Company Only Future Maturities Of Debt [Abstract]
Total debt	$ (22)				$ (29)				$ (22)	$ (29)