Depreciation and Amortization by Type (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Depreciation And Amortization By Type [Line Items]
Depreciation And Amortization	$ 560	$ 345	$ 292
Future Amortization Expense Year One	415
Future Amortization Expense Year Two	368
Future Amortization Expense Year Three	312
Future Amortization Expense Year Four	262
Future Amortization Expense Year Five	213
Internal-use software [Member]
Depreciation And Amortization By Type [Line Items]
Depreciation And Amortization	209	187	161
Other property and equipment [Member]
Depreciation And Amortization By Type [Line Items]
Depreciation And Amortization	144	117	99
Other Intangibles [Member]
Depreciation And Amortization By Type [Line Items]
Depreciation And Amortization	205	41	32
Value Of Business Acquired [Member]
Depreciation And Amortization By Type [Line Items]
Depreciation And Amortization	$ 2	$ 0	$ 0