Basis of Presentation and Significant Accounting Policies - Future Minimum Rental Commitments (Details) - USD ($) $ in Millions |
12 Months Ended | |||
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Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2019 |
Apr. 30, 2018 |
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| Lessee, Operating Lease, Liability, Payment, Due, Rolling Maturity [Abstract] | ||||
| Next one year | $ 323 | |||
| 1-2 years | 286 | |||
| 2-3 years | 220 | |||
| 3-4 years | 180 | |||
| 4-5 years | 97 | |||
| Thereafter | 424 | |||
| Total undiscounted lease payments | 1,530 | |||
| Less: Imputed interest | 206 | |||
| Present value of minimum lease payments | 1,324 | |||
| Less: Current portion | 276 | |||
| Noncurrent portion | $ 1,048 | |||
| Operating leases, rent expense, net | $ 301 | $ 314 | ||
| Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] | ||||
| 2019 | 300 | |||
| 2020 | 252 | |||
| 2021 | 210 | |||
| 2022 | 267 | |||
| 2023 | 248 | |||
| After 2023 | $ 2,040 | |||
| Office Building In New York City [Member] | ||||
| Lessee, Operating Lease, Liability, Payment, Due, Rolling Maturity [Abstract] | ||||
| Term of corporate headquarters lease agreement | 20 years | |||
| Future minimum commitment for corporate headquarters lease | $ 1,700 | |||
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due after fifth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fifth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fourth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in third rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in second rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in next rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- References No definition available.
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as current. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- References No definition available.
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Definition Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Details
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